
I think you are right Brainless, good rescue are like good breeders and will help out if one of their dogs in in trouble - the owner is happy to pay for expenses so I would have thought they would be able to help. There is also the Cinnamon Trust but they may only help when it is a case of ill health, I am not sure.
Now this is another thought for the OP to consider, from the dogs point of view it may be kinder to rehome, he will not forget you but being moved from home to home is not ideal for the dog any more than it is for you.