It sounds as if you may have unusually brittle gel-coat and I wonder whether boats built at the same time as yours--with the same gel-coat batch-are having similar problems. For what its worth, Beneteau does sell Gel-Coat patch kits in matched colors although I do not know old the boats may be before the repair kits become unavailable. Another alternative is repair kit source is Spectrum Color
I have used the Spectrum kit and found it pretty good. Frankly, I also found that a thin mix of MarineTex, applied sparingly and "polished" with 600 and then 1000 grit works pretty well too.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."