
Also there are compulsory and recommended health tests for all Kennel Club Assured breeders whenever appropriate for the breed.
Kennel club registration itself is simply a register of ancestry (like the one for human births) not anything else.
It is why those who like to criticise pedigree breeds can get ammo, as the ancestry is known, and problems can sometimes be eventually traced that way, and if occurring more often can be attributed as a breed disposition.
the crossbreed on the other hand rarely has a traceable history so where issues are coming from cannot be so easily monitored or attributed.