Dear BFH,
I should like to support the advice given by Capt. Gentil of Naples Air Centre. I couldn't have put it better myself. There isn't only one good instructor in the whole world.
I fear that treating the young with disrespect is, however, all too common even on this side of the pond. That doesn't mean you have to put up with it. you should take just so much and no more.
Is there no possibility of your instructor intervening on your behalf and telling these wallies to P** *ff. After all, if he really wants to keep your business, he should be prepared to do something to keep it.
Best wishes from Britain for a much happier New Years flying.
If all else fails let me know and I'll fly over on my flying broomstick and turn them all into human beings. (No use turning them into frogs and toads: they're clearly that already).
Good luck Kid.