I'll reply here, as I've replied private to Deano, but don't get any answer that my emails were received.
Louis come from a Kennel that is considered a "good" Kennel, successful breeder and competitor, with dogs sent all over the world. The parents are HD free, hipscored A and B. On looking into it a bit I discoverd that a full brother of Louis is competing successfully in the ring with a different owner, another dog was hipscored C and sold abroad: (minimum to breed is C, but if a C can only be bred to another animal with a score of A or B. Unfortunately last september the breeder split from his business parther and SO, this hit him so badly he became clinically depressed and apparently is in a very bad state indeed, nobody has seen or heard of him since last September. This info I was given on Sunday. He has not appeared at any shows in spain since then. The webpage and emails were managed by his ex, so the emails are not getting to him. I was given his telephone number to pass on to Deano, this I have done, and wondered if she had any luck, the person I spoke to tried to phone him then and there but he wasn't picking up his phone, as she said that if he knew, he would be on the phone to Deano (or at least the person she knew before the depression kicked in would have done so).
Another breeder I spoke to in spain asking what would she do in this case, said that it depends on the price and if it was sold as a pet or show dog. If sold at a substantial price as a breeding or show dog, she would either offer a free pup or a free mating (obviously with another bitch HD free belonging to the buyer) and offer to take the affected dog back. If the pup was sold at a lower price as a pet, she gives a guarantee against infectious diseases for a set period of time, but that would not cover HD appearing several months/year later- as these things are difficult to predict and all a breeder can do is eliminate HD affected dogs from their breeder programme, and also other factors apply such as feeding, exercise. She would offer moral support and advice, no point in offering to have the dog back as the owner would be very attached to it.