Diff self destructed.
My mate txt me 2 weeks after he had it to say he was having issues getting into gear, he popped over and it felt fine, seen hime a week later and asked him how it was and he said its ok now... following week he rang me and said he was cahnging from 3rd to 4th and it went BANG, and no drive. had it recovered to me, when we took the box out the diff was in pieces..