ROOF ANCHOR WITH PLANAR SHOCK ABSORBING MEANS TECHNICAL FIELD The present invention relates to a roof anchor for attaching devices, apparatus or equipment to a roof surface and, more particularly, to an anchor point for fixing directly to a metal roof 5 which includes shock absorbing means. The devices, apparatus or equipment to be attached may include safety equipment such as safety harnesses, ropes or other safety devices adapted to secure a roof worker against falling and injury. BACKGROUND ART Conventional roof anchoring devices require access to the roof support structure such as a .o purlin or rafter. Direct access to the support structure is generally required and involves mounting the roof anchor prior to the application of the external covering of the roof such as tiles, sarking, sheeting or other cladding so that upon application of the external covering to the support structure, the roof anchor extends proud of the external covering. However, if the external covering has already been applied to the roof support structure, .s then at least one unit of the external covering such as a tile or single sheet of covering must be removed to provide access to the roof support structure. Where part of the external covering must be removed to provide access to the roof support structure, such as for example will be the case for a completed building to which repairs, improvements or renovations are required, this may be impractical or inconvenient. Thus, for example, where 20 large units of sheeting form the external covering of the roof, considerable time and effort may have to be expended to remove a single unit to gain access to the roof support structure. Furthermore, there is also a risk that damage to the covering may occur, or more particularly, once it is re-laid, the covering might not properly seal against the elements. It would therefore be advantageous if a roof anchor were available which could be affixed 25 directly to the roofing material, with or without affixing as well to a purlin or rafter supporting the roofing material. It would also be advantageous if such a roof anchor was provided with shock absorbing means in order to minimise injury from a person utilising the anchor point and reduce the load on the structure in the event of a fall. Further, it would 1 also be desirable if the anchor point were multidirectional so that it worked efficiently no matter from which direction forces might be applied in the event of a fall. OBJECT OF THE INVENTION It is an object of the present invention to provide a roof anchor which ameliorates one or 5 more of the abovementioned disadvantages associated with the prior art, particularly by providing an anchor point which may be mounted directly to the roofing material, the anchor being so shaped as to progressively absorb the effects of a sudden load applied thereto, and wherein the anchor functions usefully in all directions. It should also be understood that whilst the invention relates primarily to the attachment of .o devices to a roof as described, the invention will also be applicable in many instances where attachment of a device to another surface or structure is required, whether a wall or ceiling for example. Thus any reference to a roof is also meant to encompass reference to any structure, where, by suitable adaptation the invention may also be utilised. DISCLOSURE OF THE INVENTION .s According to the present invention, there is provided a multi-directional roof anchor comprising a fixing region lying in a plane for fixing the roof anchor to a building; an attachment region for attaching safety equipment to the roof anchor; and a pair of serpentine shock absorbing portions lying in the plane, each serpentine shock absorbing portion being adapted to at least partially straighten on application of a predetermined load to the 20 attachment portion. At least part of the fixing region may be located between the pair of serpentine shock absorbing portions. The fixing region, the attachment region and the pair of serpentine shock absorbing portions may be formed from a single sheet of material. The attachment portion may lie at an angle relative to a plane in which the rest of the roof 25 anchor lies. In another aspect, there may be provided a multi-directional roof anchor for fitment to a roofing material affixed to a building, wherein the anchor is shaped so as to progressively distort under sudden load, the anchor having a generally planar structure, having a first 2 fixing region or regions for fitment to a roofing material, with means provided therein by which the anchor can be affixed either directly to the roofing material, or through the roofing material, to the supporting structure below; a second attachment region for attaching devices, apparatus or equipment to the anchor; and a third shock absorbing region 5 intermediate between the first and second regions and integral therewith, the third region comprising one or more shock absorbing portions, shaped so as to provide gradual or progressive absorption of a sudden load applied to the anchor as would occur in the event of a fall of a person attached thereto, the absorption provided either by the third region alone or the third region in combination with one or both of the other two regions, the anchor .o further having the ability to absorb such load when applied to it from any direction. Preferably, the roof anchor point is die cut from a single sheet of stainless steel, aluminium, high density plastics material or composite material and cut so as to provide progressive absorption of a sudden load applied thereto by means of progressive deformation under such load. .s Preferably the shock absorption is provided by one or more suitably shaped portions of material cut or otherwise formed so that when a force is applied thereto, there is created a deformation therein in the form of a generally linear extension of that portion, ie by effectively straightening or "unbending" such region. Thus the anchor is so designed that deformation by bending, ie unbending or straightening, of the third shock absorbing region o together with such other of the first or second regions where appropriate, provides an absorption of the forces applied to the anchor from any angle, that is to say if a load is exerted from any direction, the anchor is able to accommodate that sudden load by bending in suitable fashion, In this way the anchor will provide a suitable shock absorber means against for example a sudden load arising from a person attached thereto falling from the 25 roof. Preferably the means for attaching the first region to a roof material is provided by holes located in the first region. Thus, fitment of the anchor utilising the first region either directly to the roofing material or through the roofing material to the supporting structure may be achieved by any suitable means such as rivets, bolts or screws and may be achieved by 30 fixing the anchor point solely to the roofing material or fixing through the roofing material 3 so that the anchor point is also affixed to the roofing structure which supports the roofing material. Preferably the first fixing region is a single substantially linear region having a plurality of holes therethrough in linear arrangement so that the anchor may be affixed along one ridge 5 of a metal roof profile. Alternatively, the first fixing region may be provided by a pair of substantially parallel linear regions spaced apart so as to span a trough in a roof profile, the regions being fixable to adjacent ridges in the roof profile. Preferably, the roof anchor is provided with upwards of 5, 6, 7 or more holes to allow secure fitment to the ridge or ridges of the roof sheeting. The number of holes is determined by the thickness of the roofing .o material. In a first embodiment of the invention, preferably there are provided two shock absorbing portions located on either side of a single central first fixing region, whilst in a second embodiment of the invention, preferably there are provided two shock absorbing portions extending between two outer fixing regions. In either embodiment the two absorbing .s portions remote from the one or two fixing regions as the case may be terminate at a single third attachment region. Preferably the attachment region is provided with a hole therethrough for attaching devices, apparatus or equipment in known fashion. Alternatively the attachment means is provided by a loop or bridge between the pair of absorbing regions. 20 Preferably, there is provided in any of the embodiments one or more breakable joins or connections between the first fixing and second attachment regions, which are designed to prevent the anchor from simply bending under initial load, but fails at a pre-determined load, whereby the load is then essentially exerted on the absorbing section(s) progressively. It will be understood from the embodiments described herein, that the design is able to 25 function irrespective of the direction of the load. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following non-limiting description of various embodiments of the present invention with reference to the drawings in which: 4 Fig 1 is a perspective view of a roof anchor according to one embodiment of the invention, with one end region bent; Fig 2 is a plan view of the roof anchor shown in Fig 1 before bending; Fig 3 is a plan view of a roof anchor according to a second embodiment of the invention; 5 and Fig 4 is a plan view of a roof anchor according to a third embodiment of the invention. DETAILED DESCRIPTION OF THE DRAWINGS Referring generally to Figs 1 and 2, there is shown a roof anchor generally referenced 11 according to a first embodiment of the invention. The roof anchor 11 is made from a single .o sheet of stainless steel material 3mm thick, die cut as shown. The anchor comprises a central portion 12 for affixing along the length of a rib in a sheet of roofing material (not shown). This central fixing portion 12 is provided with several holes 13, in this case seven, along its length through which suitable fastening means are employed, eg special rivets which can't be over-tightened, in order to affix the roof anchor .s 11 to the ridge or rib of the sheeting material. Extending laterally on either side of the central fixing portion 12 are two snake like regions designed to act as shock absorbers 14 when a load is applied to the anchor 11, as would occur in a fall of a person attached thereto. One end of each shock absorber region 14 extends from an area roughly halfway along the 20 central fixing portion 12 and the other ends thereof respectively terminate in a bridge portion 15 extending therebetween which provides an attachment region to which a cable, safety harness, rope etc (not shown) may be attached. As shown in Figure 1, this attachment bridge portion 15 is conveniently bent upwards at a right angle to the plane of the rest of the anchor 11, but in practice this is not necessary and any convenient angle may be chosen, or 25 the bridge 15 not bent at all. In the vicinity of the region where each shock absorbing portion 14 becomes the bridge region 15, there are provided small spanning joins 16 extending between that part of the shock absorber 14 and the nearest point on the fixing portion 12, the purpose of which is to 5 provide break points so that the initial load applied to the anchor 11 should a fall be experienced, does not cause the shock absorbing regions 14 to come into play until a predetermined initial load has been experienced. In this way initial unwanted bending of the anchor 11 at a single point is avoided. 5 It will also be appreciated that no matter from which direction a load is applied to the anchor 11, ie no matter which direction a person falls who is attached thereto, the anchor 11 will still function effectively, the shock absorbers 14 on either side sharing to a greater or lesser degree the load and suitably deforming depending on the direction of the load. Even if the load is experienced from the end of the anchor 11 opposite that of the attachment .o region 15, the anchor 11 will still work effectively, the initial load breaking the joins 16 at a predetermined load level and then the shock absorbing regions 14 being only then bent back but otherwise then extending at the same time to absorb the load. Thus when a load is applied to a cable or rope etc attached to the attachment region 15 of the anchor 11 , it causes the break points 16 to give way at a predetermined load, and then .s the shock absorbing regions 14 progressively bend (ie extend or appear to unbend), so that the load is absorbed more slowly, thereby reducing the risk of injury from someone having fallen. Referring generally to Figs 3 and 4, there are shown two additional embodiments of a roof anchor 11 according to the invention, in which like components are referenced with the 20 same numerals for ease of comparison. The embodiment in Fig 3, is generally similar in structure to that of the embodiment in Figs 1 and 2, having a central fixing portion 12 and two shock absorbing regions 14 extending either side thereof. Again they commence about mid way along the fixing portion 12 but instead of terminating at the other end in a bridge region, they join together at a generally 25 ring like portion 15' which acts as an attachment point, in the same as the bridge portion 15 of the earlier embodiment functions. Further, instead of two join points 16 as shown earlier, here the roof anchor of Fig 3 is provided with one point 16' only. The overall function of the roof anchor 11 in this embodiment is otherwise similar to that described above for the first embodiment. 6 The third embodiment of a roof anchor 11 as shown in Fig 4 is different in so far as it is provided with a pair of generally parallel fixing portions 12' which are able to span the valley of a roof sheeting material, so that each fixing portion 12' may be affixed to consecutive ridges of the sheeting material (not shown). Instead of extending outwardly 5 from a central fixing portion 12' as in the earlier embodiments, this embodiment again has two shock absorbing regions 14 but this time they extend inwardly of each of the two fixing portions 12'. Again they extend from the fixing portions 12' roughly mid way along their lengths, and again terminate in an attachment ring 15' in similar fashion to that of the second embodiment. .0 In this case, two join points 16 are again provided as shown, conveniently located so as to connect the shock absorbing regions 14 to the ends of the fixing portions 12' in similar fashion to that described for the first embodiment. Again, although this structure is inherently different from those of the first and second embodiments, at least visually, it will be appreciated to those skilled in the art, that in .s essence, the third embodiment functions in like fashion to the other embodiments. It will be appreciated that many modifications and variations may be made to the embodiments described herein by those skilled in the art without departing from the spirit or scope of the invention. Throughout the specification and claims the word "comprise" and its derivatives are 20 intended to have an inclusive rather than exclusive meaning unless the context requires otherwise. INDUSTRIAL APPLICABILITY It will be immediately apparent to persons skilled in the art that the roof anchor may provide an anchor point for a variety of activities carried out on roofs. For example, the roof 25 anchor may provide an anchor point for posts supporting fences or other barriers erected for the safety of workmen working on the roof or may be used to secure equipment associated with the actual work on the roof. Moreover, the roof anchor may provide an anchor point for fittings such as solar panels or water heaters required to be mounted on the roof. 7