I've been doing loads of research and there is a perfect Kennel Club registered pup who will be ready in 6 weeks.
KC registration is no guarantee of a decent breeder, all it means is that both parent dogs were registered.
This is a really good, concise guide to finding a decent breeder. It's well worth reading their list of questions to ask a breeder as well. If you want something a little more in depth try this, it's from the American Kennel Club but the information is all still relevant.
The breeder should thoroughly grill you, not just be happy to hand over a puppy if you've got the money. Expect them to ask why you want that breed, why you chose them as a breeder, what you feel you can offer a dog, what you are hoping for in a dog, etc.
As far as health testing goes both parents should have been hip scored (with a score lower than 10), elbow scored (with a result of 0) and have current BVA eye tests (these are repeated annually).
At an absolute minimum both should have been DNA for (or be clear by parentage of) prcd-PRA, Hereditary Nasal Parakeratosis, Centronuclear Myopathy and Exercise Induced Collapse.
The litter should also be screened by a BVA eye panellist for signs of Multifocal Retinal Dysplasia.
Ideally they should also have been tested for (or be clear by parentage of) Achromatopsia, Leukodystrophy, Congenital Myasthenic Syndrome, Cystinuria, Degenerative Myelopathy, Skeletal Dysplasia, Macrothrombocytopenia, Narcolepsy, Pyruvate Kinase Deficiency, Oculo Skeletal Dysplasia and X-linked Myotubular Myopathy.
The litter should have a coefficient of inbreeding lower than the breed average (which in labs is currently 6.5%) but preferably as close to 0% as possible. This blog post gives a good explanation of why COIs are so important.
The breeder should be happy to show you all relevant paperwork for all the health tests as well as talk you through both them and the inbreeding coefficient of the litter.
If you have the KC registered names of the parents you can use the Kennel Club Mate Select service to check the COI of the litter and for health test results for the parents. Bear in mind though that currently not all the available DNA tests will show up on those results.
Preferably the breeder should be doing something with their dogs whether showing, working, taking part in dogs sports, PaT dog qualifications, even the KC Good Citizen Dog Scheme awards. Just something which indicates they're keen to test their dogs either physically or mentally (or ideally both) prior to breeding from them.
They should also have a good working knowledge of dog conformation (their physical structure), how it potentially affects the dogs in question, be able to identify shortcomings in their bitch and explain why they picked that particular stud dog to improve them.
They should have picked the best possible stud for their bitch in terms of complimentary conformation, temperament, health test results and prospective litter COI rather than just using one because they also happen to own him or he only lives down the road. The best possible match for any bitch in terms of producing healthy, well put together pups of great temperament is rarely the closest one.
Finally, they should be putting a lot of effort raising these puppies. Far too many breeders just let the bitch get on with it then do the absolute minimum to keep them clean and vaguely stimulated once they're weaned. This site gives you a good idea of the minimum the breeder should be doing during each stage of the puppies' development. Ideally they should have made a start on toilet training (proper toilet training, not just getting them to go on pads) and also started getting the puppies used to being separated from the litter. The absolute gold standard of puppy raising is the Puppy Culture method and I'd highly recommend it to prospective puppy buyers as well as it covers right up until twelve weeks old. There's an excellent FB group where you can see breeders utilising the methods and the difference it makes to the puppies.
This puppy will hopefully be part of your family for well over the next decade, it's really worth putting in the extra effort and time to find a really great breeder who is not only doing everything they can to produce healthy, happy, well rounded puppies but will be also be there to support you should you need it throughout the life of your dog.