Most pet shops that sell puppies get them from illegal puppy farms so please do not to consider them.
Pedigree breeders tend to be ethically much better of course, especially those that invest a lot in doing all the medical checks – look up what tests are relevant to the breed and ask them about it. They tend to have a long waiting list though and some pedigree breeds can have genetic problems especially in UK where the kennel club has been historically crap at controlling inbreeding, the average inbreeding coefficient for Border terriers is well above 5% i believe.
Alternatives..
Get chatty with the local people walking their dogs if you are lucky they might know somebody who has a litter coming.
We found our BorderSausageJackShih on gumtree, it was a bit of effort filtering out the scammers and puppy farmers but we eventually found a family in essex that had some puppies, both parent doggies were there with the puppies it was a mad but happy house of dogs and cats, they had basically adopted unwanted dogs and wanted each to raise a litter before they nutered them.
