
Check the bigger breeders who may well have a retired, and probably spayed bitch who they'd love to get out of kennels and into a loving fireside home for the rest of their lives. Do this via the relevant Breed Clubs preferably as that should help you avoid BYBs.
You might also look on the Dogs Trust website as they quite often have Labs in. Also a Breed Rescue. Hope you are successful because right now, Shelters are inundated with enquiries for purebred dogs as puppy prices have gone through the roof.