> I presume pups not reg with KC are cheaper
KC registration is only £12 per puppy. Lack of KC registration to me means they can't be registered for some reason.
As the requirements of KC registration are only:
that both parents are themselves registered
that the bitch must not have been mated before 1year of age, not be over 8 years old at whelping, and not already had 6 litters.
that there were no breeding restrictions still in place, placed on either parent by their previous owner/breeder.