We researched our breeder. Apparently being KC registered means very little. You pay a small amount for a piece of paper.
Yes and no. It's not a guarantee of quality (a pup can be registered merely if both of its parents have) but in theory it should mean that the mother of the puppies hasn't been bred every season (as there's a maximum number of litters allowed), too young or too old (as there are rules on that too) and that required health tests for the breed concerned have been carried out before the mating took place. Test results are kept on record at the KC and can be easily checked.
The Kennel Club will not register some of the 'rare' colours people seem to like these days because they are associated with serious health problems, so if you're on the lookout for - say - a merle, cream or lilac French bulldog, it's not the breeder's choice not to register, it's that it won't be accepted.
Being licensed is a much better indication of a good breeder as they have to pay £500 and are inspected annually.
Being licensed is, sadly, an indication of a breeder who will pay £500 and put up with being inspected annually - a snapshot of the conditions of premises and dogs on that day, not an examination of breeding practices, pre-mating health testing or long term health of the dogs. £500 is a third of the price of one puppy at the price you're paying. Small beans. And being licensed often means multiple bitches of multiple breeds being bred multiple times.
The Kennel Club is not the answer to dog welfare in this country but neither is licensing, sadly. It's very much a case of 'buyer beware'.