the correct response (if you are a member of the royal yachting association) should be, is this club a member of the royal yachting association? if the answer is in the affirmative, then would be the time to remind him of the unilateral agreement between member organisations of the Royal yachting association, that members of the RYA can use the facilities of any member organisation, I currently assist at a Norfolk broads forum, that is going for affiliated membership of the RYA (along with all the benefits that entails) which will mean any of our members could legitimately use the facilities provided by many of the posy yacht clubs (even if they are on a hire boat)
snobbishness like this always gets my goat
well looking at their webpage and considering they are a RYA training centre and are displaying a RYA on board sign prominently, it looks as though they could be in for a surprise visit or several.
I will see if I can find a quote saying this is so.