Well I passed my CPL skills test landing in a 20kt crosswind in an aeroplane with a max demonstrated of 17kts. Of course, if I hadn't recognised and announced the situation I would have failed. But I think it is an example that the demonstrated is not a limit.
I belive, the demonstrated could simply be the highest crosswind that the test pilot had the opportunity to fly. Therefore I would be very suprised if such a situation would compromise your insurance.