
As you are interested in showing I would contact the breed clubs for advice and a list of members that are planning litters. Being members of the club they are more likely to be breeding with the breed standard in mind, having a deep interest in the breed.
There are a lot of Cavs out there bred by folk who don't know the difference between a good and bad one. Some of these are commercial breeders and puppy farmers, and others just breeding from Flossie for the pet market.