Having made a good start on working out what needed doing I turned the boat over to inspect the inner skin.
Inside the cockpit for repairs I came across another nasty surprise. I already knew that the topside was cracked just at the chine at this point as mentioned before. As I stripped the paint off I rapidly became aware of a large area of glass fibre, which had been well faired and filled on the outside, but rather more slapped on from this side. Coupled with the crack against the gunwhale, plus the cracks through the skin below (circled) its quite obvious that at some time there was a pretty nasty collision. By the look of things it got patched up quickly, and then never revisited.
There was also another area of dubious glass reinforcement in the transom area above the cracks found with Nasty Surprise1. For some reason the outer skin seems to be in much poorer condition than the inner skin in this area, and probably the whole area where the hull goes down to single skin will need reinforcing.
So having established all this I started to get on with Cleaning up the Inside of the boat.