Oh DillyDolly I am so sorry to hear about poor Dilly, it must have been devestating. We had a rescue GSDx PTS 6 years ago, and it is still painful to think about those last few days when we knew what we had to do (she was only 5)
And how awful that his breeder wasn't interested in his allergies, and so doesn't know he's gone - its scary to think that she is probably still breeding, and is likely to have a good reputation, and considered to be responsible; I wonder how many other litters had pups with these problems? Did you tell the Kennel Club - surely the breeder should investigate any reported heath problems?
I always tell them not to buy from these pet stores and explain my reasons why and they are quite amazed and thought that these places were the right places to buy from!
This is one of biggest gripes - puppy farmers and stores advertise and promote their puppies, so when anyone begins their search, this is what they see and respond to. Reputable breeders on the whole, don't advertise, so it can be a real detective job to even find a breeder; you have to join the local doggy circle long before you have got a doggy