I have just got back from viewing a composite Wayfarer down in South Wales. The ebay pictures looked superb and on arrival the boat looked as good as in the photographs. That was until I removed the floorboards to have a look at the structure. Every floor support was showing signs of cracks and of breaking away from the hull. A bit of a push on the side showed the bearers moving independently from the hull.
All this damage was caused by the hull resting on its bilge keels instead of its keel. What a shame. Needless to say we came away without it. But worth mentioning here as a reminder to everyone to check your boat rocks just a little when on its trailer and also to do as I did when viewing a boat. Remove the floorboards and check for cracks.
Though I agree with what you said, it would not put me off buying the boat. The supports are relatively easy to fix with 50 quid worth of fibreglass and epoxy. I would use it to negotiate a better deal though.