Lisa, if your boy is not going to be a show cat, then I really wouldn't be worried about the kink in his tail. Yes, it is a fault that would be penalised on the bench as far as pedigree cats are concerned, but if his sole goal in life is to have a worshipful human
owner slave at his beck and call, then it shouldn't be an issue.
Worth having a chat with the breeder though - a good breeder won't fob you off and will be more than happy to discuss things through with you.
Having said that, a friend of mine shows a black & white boy who has a double kink in his tail in the household pet classes - but in HP, it's all about condition and temperament rather than perfection and looks. Kinky's tail, despite its interesting s-bend doesn't bother him whatsoever.