Sorry Robert - but on the off chance one slipped through this safety net I contacted several rescue centre managers and asked if they would inform me of in this eventuality - all said NO...none of my business once they recieve the dog. That's the difference between a good rescue and a bad one, If I was contacted by a breeder then I would be delighted to let them have the dog back, having said that though, I can see that the rescue managers said "No", because the dog is in their care they would have a duty to ensure the dogs on going welfare, and there maybe other implications which would mean the dog couldn't be returned, legal, or what ever, that shouldn't mean an out of hand "NO" though, the managers. I would have thought would have explored the possibility of returning the dog.
Putting all that a side, I don't see any reason for any one not to be civil on the telephone or unhelpful, I've been on the end of those calls too when I've contacted breeders about dogs, and also other rescues that have had the breed in that I deal with, I've called offering to take the dog, sign a change of ownership contract, assume all responsibility, both financial and welfare, only to have the same response as you have, oddly one of the rescues I contacted made local radio and local newspaper appeals for money to help this dog, but refused dedicated breed rescue help, perhaps the rescues have other motives for not passing the dog to other parties.
BTW she also had a serious cat chasing problem when we got her -that wasn't on show either as there were no cats in the rescue. I would consider it a minimum requirement of any dog put up for re homing to be properly assessed for all that it may encounter in a home, other dogs, cats, children, vacuums, livestock, the big outside world, where it's not possible then surely that is relevant information and should be passed on to potential owners, likewise, potential new owners should assess the dog them selves, spend time with it, ask questions and go away and consider all things for a few days.
A rescue is an open book in that you know it hasn't got the health checks, knowing that you would not reasonably expect guarantee's on it's health, nor would you expect guarantee's on a puppy whose parents have all the relevant health checks, for example, my understanding is that environmental factors have an impact on dogs hips, hence we in the know don't allow puppies to run up and down stairs or go for long walks early on in their development. I also understand that some eye tests are like a an MOT on a car, they show the dog is clear on the day it was tested, next step could show up a problem, other health problems can surface with out prior warning in dogs from previously healthy stock.
Also an open book in that, if properly assessed you have a pretty good picture of what the dog is like, likes, dislikes, etc.