5 A FENCE TECHNICAL FIELD 10 The present invention relates to a post and rail fence made from steel. More particularly, the present invention relates to a steel fence that includes two spaced-apart upright support posts, a top rail and a bottom rail extending between the posts, and three infill panels formed from steel strip positioned between the posts and having upper and lower ends supported by the rails. 15 BACKGROUNDART Safety and cost are important issues for fences that are used, for example, to separate adjacent suburban properties and in other applications. 20 The fences require sufficient structural integrity to withstand loading, such as wind loads (particularly in high wind areas) and children or adults climbing over fences. The requirement for structural integrity is a factor that has a direct bearing on the construction of the fences, including the steel gauge, the length of spans between fence support posts, and the profile and the size of the posts, rails and infill panels. In the 25 final analysis, the amount of steel in the fences and the structure of the components that make up the fences have a direct impact on the cost of the fences. The above references to the background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art. The above references are also not intended to limit the application of the fence 30 as disclosed herein. SUMMARY OF THE DISCLOSURE The present invention provides a fence that includes two spaced-apart upright 35 support posts, a top rail and a bottom rail extending between the posts, three infill panels formed from steel strip positioned between the posts and having upper and lower 1 3570081_1 (GHMaters) P91076.AU 5 ends supported by the rails, with adjacent panels having overlapping sides, a plurality of fasteners securing the panels and the rails together at the overlaps of the panels to improve the structural integrity of the fence, and a plurality of fasteners securing each panel and the rails together to improve the structural integrity of the fence. The applicant has found that the above-described fence has sufficient structural 10 strength to support wind loads (particularly in high wind areas) and children and adults climbing the fence. The fence may include at least one fastener securing a pair of overlapping panels and the top rail together at the overlap of the panels. The fence may include at least one fastener securing a pair of overlapping 15 panels and the bottom rail together at the overlap of the panels. The fence may include (a) at least one fastener securing a pair of overlapping panels and the top rail together at the overlap of the panels or (b) at least one fastener securing the pair of overlapping panels and the bottom rail together at the overlap of the panels. 20 The fence may include (a) at least one fastener securing a pair of overlapping panels and the top rail together at the overlap of the panels and (b) at least one fastener securing the pair of overlapping panels and the bottom rail together at the overlap of the panels. The fence may include (a) a plurality of fasteners securing each panel and the 25 top rail together or (b) a plurality of fasteners securing each panel and the bottom rail together. The fence may include (a) a plurality of fasteners securing each panel and the top rail together and (b) a plurality of fasteners securing each panel and the bottom rail together. 30 Each panel may be made by roll-forming or pressing steel strip into a suitable profile. Each panel may be formed from steel strip that is less than or equal to 3.5 mm gauge steel. Each panel may be formed from 3.5 mm gauge steel strip. 35 Each panel may be made from corrosion resistant metal alloy-coated steel strip. Each panel may be a profiled panel. The profile may be any suitable profile. 2 3570081_1 (GHMaters) P91076.AU 5 For example, each panel may include a series of parallel ribs extending along the length of the panel. The ribs may be open ribs or closed ribs. The ribs may be at least 20 mm deep. The width of the ribs may be at least 80 mm. 10 Each panel may be rectilinear and include two parallel sides and two parallel ends. Each panel may be at least 1700 mm long and at least 700 mm wide. Each panel may be at least 1700 mm long. Each panel may be at least 750 mm wide. 15 Each rail may be an elongate channel having a base and opposed sides extending from the base, with the sides defining an open mouth, with upper and lower ends of the panels extending through the open mouths and received in the channels of the rails. The rails may be formed from corrosion resistant metal alloy-coated steel strip 20 that is less than or equal to 3.5 mm gauge steel. The posts may be channel-shaped in transverse cross-section. Each post may be an elongate channel having a base and opposed sides extending from the base, with the sides defining an open mouth, with sides of the panels and ends of the rails extending through the open mouths and received in the channels of 25 the posts. The posts may be spaced-apart by at least 2200 mm, measured between the centres of the posts. The posts may be spaced-apart by at least 2300 mm, measured between the centres of the posts. 30 The posts may be formed from corrosion resistant metal alloy-coated steel strip that is less than or equal to 3.5 mm gauge steel. The posts may include post stiffeners. The post stiffeners may be rigid elongate members, such as steel plates, secured to the channel-shaped posts. 35 The posts and the rails may be formed from corrosion resistant metal alloy coated 3.5 mm gauge steel strip. 3 3570081_1 (GHMaters) P91076.AU 5 The fasteners may be spaced apart between 10 and 30 mm. The fasteners may be spaced apart between 15 and 25 mm. The fence may include a plurality of unit lengths, with each unit length including the above-described fence having two spaced-apart upright support posts, a top rail and a bottom rail extending between the posts, three infill panels formed from 10 steel strip positioned between the posts and having upper and lower ends supported by the rails, with adjacent panels having overlapping side edges, a plurality of fasteners securing the panels and the rails together at the overlap of the panels to improve the structural integrity of the fence, and a plurality of fasteners securing each panel and the rails together to improve the structural integrity of the fence. 15 The present invention also provides a fence kit for constructing the above described fence that includes a plurality of the posts, rails, infill panels and fasteners. BRIEF DESCRIPTION OF THE DRAWINGS 20 Notwithstanding any other forms which may fall within the scope of the fence of the invention as set forth in the Summary, a specific embodiment will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a front view of a section of an embodiment of a fence in accordance 25 with the present invention; Figure 2 is a front view of a section of another embodiment of a fence in accordance with the present invention; Figure 3 is a front view of a section of another embodiment of a fence in accordance with the present invention; 30 Figure 4 is a side view of a longer section of an embodiment of a fence in accordance with the present invention that includes a plurality of unit lengths of the fence shown in Figure 1; Figures 5(a) to 5(e) are perspective and cross-sectional views of the main components of the fence shown in Figure 1; 35 Figure 6 is a vertical cross-section through the part of the fence enclosed by the circled area of Figure 1; and 4 3570081_1 (GHMaters) P91076.AU 5 Figure 7 is a horizontal cross-section through a section of the fence shown in Figure 1 that illustrates the overlap of two infill panels of the fence. DESCRIPTION OF EMBODIMENTS 10 The embodiment of the fence 3 in accordance with the present invention shown in Figure 1 includes: (a) a pair of spaced-apart support posts 5 secured in footings 25 in the ground 37, (b) a top rail 7 and a bottom rail 9 extending between and connected to the posts 15 5, (c) three infill panels 11 having parallel sides and parallel ends positioned between the posts 5, with upper and lower ends being supported by the top and bottom rails 7, 9 respectively, and adjacent panels 11 having overlapping sides with the overlap being indicated by the numeral 35, 20 (d) fasteners 21 securing each panel 11 and the rails 7, 9 together, (e) fasteners 13 securing adjacent panels 11 and the rails 7, 9 together at the overlap of the panels 11, and (f) post stiffeners 23 in the form of elongate plate members secured to the support posts 5. 25 The fasteners 13, 21 are provided to improve the structural integrity of the fence. The embodiments of the fence 3 in accordance with the present invention shown in Figures 2 and 3 are very similar to the embodiment shown in Figure 1 and the same reference numerals are used to describe the same features. The main differences 30 between the fences is that the Figure 2 fence does not have post stiffeners 23 and the Figure 3 fence has a shorter post stiffener 23 than the Figure 1 fence. Figure 4 illustrates a longer section of a fence in accordance with the present invention. The longer fence section includes a plurality of unit lengths of the fence section 3 of the type shown in Figure 1 positioned in side-by-side and interconnected 35 relationship. In effect, Figure 1 illustrates a unit length of fence 3, which can be repeated as required to form a desired length of fence. 5 3570081_1 (GHMaters) P91076.AU 5 The main components of the fence 3, namely the posts 5, the rails 7, 9 and the infill panels 11, are illustrated in Figures 5(a) to 3(e). The profiles of the components shown in the Figures are examples of a wide range of different possible profiles for the components. The Figures include examples of dimensions for some of the components. These dimensions are examples of a wide range of different possible dimensions for the 10 components. The components are roll-formed from metal-coated steel strip. The components may be pressed or otherwise formed from steel strip. With reference to Figures 5(a) and 7, each infill panel 11 is in the form of a profiled panel forming a series of parallel ribs "X". Each rib "X" includes a base 15 and a pair of diverging sides 17 and which terminate in short flanges 21 (shown only in 15 Figure 7) that are parallel to the base 15. With reference to Figures 5(b) and 5(c), the top and bottom rails 7, 9 are in the form of elongate channels each having a base 31 and sides 33 extending from the base 27 and defining an open mouth that is shaped to receive respective upper and lower ends of the infill panels 11. 20 With reference to Figures 5(d) and 5(e), each post 5 is also in the form of an elongate channel with a base 27 and sides 29 extending from the base 27 and defining an open mouth that is shaped to receive sides of the infill panels 11 and the ends of the rails 7, 9. One specific example of the fence 3 has a nominal post-to-post span of 2350 25 mm and includes infill panels 11 that are 1800 mm high and 860 mm wide and are roll formed from 3.5 mm gauge metal alloy-coated steel strip. The infill panels 11 are profiled as shown in Figures 5(a) and 7, with the panel ribs "X" being 24 mm deep and having a width of 88 mm. The fasteners 13, 21 may be any suitable fasteners. For example, the fasteners 30 may be (a) self-drilling, self-tapping hexagonal washer head screws, (b) self-drilling, self-tapping long drill bit hexagonal head screws, or (c) self-drilling, self-tapping hexagonal head screws. Figure 7 is a horizontal cross-section of a section of the fence 3 that illustrates the overlap of a pair of the infill panels 11 of the fence 3. The overlap is indicated by 35 the numeral 35 and a fastener at the overlap is indicated by the numeral 13. The three panels 11 are overlapped in the same way. 6 3570081_1 (GHMaters) P91076.AU 5 Figure 6 is a vertical cross-section through the part of the fence that is enclosed by the circled area of Figure 1 and illustrates the engagement of a fastener 13 with the infill panels 11 and the top rail 7 at the overlap of the pair of panels 11 at that location. The fastener 13 penetrates one side 33 of the top rail 7 and the overlapping panels 11. There is the same engagement of another fastener 13 with these panels 11 and the 10 bottom rail 9 at the overlap of the panels 11. The engagement is important in terms of providing the required structural integrity for the three infill panel fence 3 having the typical dimensions, including a nominal post-to-post span of 2350 mm, described above and shown in the Figures. With reference to Figure 3, the fasteners 21 secure each infill panel 11 to the top 15 and bottom rails 7, 9. The fasteners 21 are spaced apart between 15 and 25 mm and are positioned to extend through the base 15 of each rib "X" of the panels. The engagement of the fasteners 21 and the infill panels 11 and the top and bottom rails 7, 9 as illustrated in Figures I to 3 is important in terms of providing the required structural integrity for the three infill panel fence 3 having the typical dimensions, including a 20 nominal post-to-post span of 2350 mm, described above and shown in the Figures. The fence 3 may be installed as described below. 1. Layout stringlines to position your fence Lay string lines to mark the outside line of the posts 5 and help to set the posts at a required height. 25 2. Layout posts and dig holes Determine the positions of the posts 5. Lay the rails 7, 9 on the ground butting end to end between the posts. For raked sites, longer rails may need to be used. If there is to be a gate, locate the gate posts. Dig the holes. 30 3. Place the first post If the ground slopes, start at the high end. Lay a minimum of 40 mm concrete under the end of the first post 5 and set the post into the hole. Fill the hole with concrete. Ensure that the concrete tapers away from the post. 35 4. Place remaining posts 7 3570081_1 (GHMaters) P91076.AU 5 Place the second post 5 in its hole and engage a bottom rail 9 with the first and second posts 5. Make sure the bottom rail 9 is 50 mm above the ground. Fasten the bottom rail 9 with one hexagonal head screw from both sides of each post 5. Use the string line to ensure the posts 5 are all the correct height, plumb and in line, before concreting into position. Wait at least 24 hours for the concrete to dry before installing 10 infill panels 11. Continue installation of the posts 5 and the bottom rails 9 for the remainder of the run. 5. Installing infill panels Insert a first panel 11 flush into the bottom rail 9, usually about 200 mm out 15 from the post 5. Lift the top rail 7 and slowly slide the panel 11 into the top rail 7. Slowly ease the first panel 11 along the rails until it contacts the post 5. Use the same process to position the second infill panel 11, with an overlap with the first panel 11. Ensure that there is the required overlap with the first panel 11. At this stage some minor adjustments may be necessary to get the lap to sit correctly or to fit the panel 11 20 into the bottom rail 9. Repeat the process for the third panel 11. The third panel 11 is the most difficult. Place the bottom of the panel 11 into the bottom rail 9, ensuring there is overlap to the second panel 11. Once the third panel 11 is in position, gently tap the top rail 7 down onto the panels 11. The fence requires the fasteners 13 to be engaged at the top and bottom of the overlaps of the three infill panels 11 as shown in 25 the Figures. The fasteners 13 should pass through the infill panels 11 into the rails 7, 9. Each fastener 13 should pass through the laps. 6. Fixing infill panels to rails From one side, fasten infill panels 11 to both top and bottom rails 7, 9 with the 30 fasteners 21. The applicant has found that the above-described fence 3 with three infill panels 11 and fasteners 13 that secure the panels to the top and bottom rails 7, 9 at the overlaps of the panels and fasteners 21 secure the panels 11 to the top and bottom rails 7, 9 has sufficient structural strength to support wind loads and children and adults climbing the 35 fence. 8 3570081_1 (GHMaters) P91076.AU 5 Many modifications may be made to the embodiments of the invention described herein with reference to the Figures without departing from the spirit and scope of the invention. By way of example, whilst the above-described embodiments of the fence 3 include fasteners 13 connecting together the infill panels 11 and the top rail 7 and the 10 bottom rail 9 at the overlaps of the panels 11, it can readily be appreciated the invention is not limited to this arrangement and extends to arrangements in which there is only one (or more than one) fastener 13 connecting together each pair of infill panels 11 and one of the top rail 7 and the bottom rail 9 at the overlap of the panels 11. In the claims which follow, and in the preceding description, except where the 15 context requires otherwise due to express language or necessary implication, the word "comprise" and variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the fence as disclosed herein. 20 9 3570081_1 (GHMaters) P91076.AU