If you are a registered breeder with GCCF then you are supposed to abide by their rules i.e. to keep the kittens until they are 13 weeks. I guess it is probably due to the fact that pedigrees may mature a little more slowly than moggies (I am sure someone will be able to advise of the reasoning behind this better than I can!). Either way I personally would be wary of any pedigree breeder letting their kittens go earlier than the 13 weeks (well a few days earlier is probably okay but more than a week.......