Steve Messham claimed that it was the policeman who showed him pictures of his abusers who identified one of them as McAlpine.
This seems unlikely to me, to put it politely. He's either lying, McAlpine is lying or there is a policeman somewhere who for some reason wrongly named the person in the photo.
Additionally, the person that the MP Tom Watson refers to in relation to the Bryn Estyn abuse is probably a different person, not McAlpine anyway.
There's a lot more digging to be done there I think, but of course many have now been scared off from doing so by the threat of legal action.
As I said before it's hardly surprising Jimmy Savile got away with what he did when we see this.