Mine is a Mark 2 but I am sure the Mk 1 is similar and the striking thing I but notice is that your GRP tabernacle is missing! It has been replaced with timber and through those penny washers and screws the timber is providing the structural support to the rear of the foredeck. The attached image is of my tabernacle, which you can see is in GRP laminated to the centreboard moulding and the underside of the deck.
The pattern of cracks and stress fractures on yours suggests (to me at least) that at some stage the GRP tabernacle sides have been removed and then the deck subjected to some vertical load near the edge, perhaps someone stepping onto the fore deck to take a mooring? Crunch. Perhaps the timber sides were added after the damage occured to strengthen the deck. The GRP tabernacle has three sides, your timber one only has two, maybe there is sufficient movement between timber and deck to continue to propagate the cracking.
You still have the basic shape of the deck edge so you might be able to grind away the gelcoat and repair the outside cosmetically using epoxy and woven cloth (not chopped strand and polyester), and filler which you will need to protect from UV by painting it or varnishing over the repair. You then need to beef up the deck structure underneath, I would suggest you use formers to create “top-hat” sections to give the repair some depth overlaid with 5 or so layers of cloth and epoxy. I use foam obtained from cfs glassfibre (http://www.cfsnet.co.uk/) to make formers.
I suppose the timber is doing the appropriate job of providing support and if you cannot obtain glassfibre sides to the tabernacle, (maybe Porters have spare ones?), then doing a better job of fixing the timber would be ok, your solution should however not leave those screws and washers which I suspect will damage your mast, at least scratching the anodizing and at worst introducing a point load at the point of maximum stress.