Just to let you all know that I finally managed to catch up with the neighbours a few doors away and they are still in contact with my former next door neighbour.
Turns out that the son had been working with one of the father's friends down Devon way but had just disappeared without letting anyone know. Before that he had been staying with a relative of the second set of neighbours in a nearby village. Feel relieved as I found it difficult to believe that his parents would have thrown him out like that and it had to be a misunderstanding. second set of neighbours are going to contact first set and let them know he has been spotted - and also contact the cousin to see if he is back there so at least everyone knows he's still alive even if we don't know where he is now.