You should contact your breeder and the CKC. Welsh Terriers are recognized by the CKC.
I should have noted, many people do like the UKC for it's competitive venues and will double register so they can compete in UKC and CKC. However any breeders I know will only do CKC for conformation and sports. I know some of that is because they only have so much money available for membership, entry fees and travel to competition so they concentrate on the only one that allows them to legally represent their dog as a purebred in Canada.
Why do you want your dog to be registered with the Canadian Kennel Club?