You done the right thing Nix, the animal was in bad shape when you took it in, you fed it, took it to a vet, obviously the original owner isnt capable of looking after it properly, consult the rspca, theyll soon understand if an animal has been neglected in any way, and support the case of someone who's prepared to look after it properly. If someone cant look after an animal properly they shouldnt be allowed to keep it.