Since it is not the breed of a dog, per se, that I respond to, Sorcha, a faked breed would not matter to me personally. As for the Norwich and the Cairn breeds they are similar enough that if a breed's characteristic did matter to me I'd be happy with either.

However, the Norwich is appreciably smaller than a Cairn so it might be difficult to pass one off as the other.

I read about it in Wikipedia- and the whole thing doesn't make sense to me.