Welcome to the forum Susan.
I think that you are probably looking for a needle in a haystack! Even if you can locate the breeder, she must have had a reason not to register your dog? I wouldn't get my hopes up on being able to register him.
Its a very long shot, but have you tried the breed club?
Manchu Shih Tzu Society on 01795 830247.
They will also be able to tell you about the necessary health checks etc that can be carried out before any mating takes place. You may also find this link on
Breeding of interest.
Leigh