It occurs to me that Uncle Gerry is probably heavily influenced by the Moors Murderers, whose arrest and trial likely happened around the same time as Forest was writing RMF: its a stereotype which has since become lurid and conventional, but was probably simply topical in the late 60s given the immensely high profile and widespread horror generated by the case. So I didn't have my historical googles on there, for which, apologies.

I don't think it matters a great deal in the long run what Foley's motivation is (or whether he has one--he's explicitly stated not to have much of a motivation for spying in the first place) as long as the right atmosphere of inchoate wrongness is created, which it is, very effectively. But for me personally, Nicola's reaching for the analogy of bullies in boys' school stories is a very 1940s way of trying to articulate the abuse of power dynamic that she sees in the story Peter tells. And sexual abuse is nearly always a strand in those stories--I think it's probably the rare boys' school story that doesn't raise the idea of 'beastliness', if only to dismiss it: the 'Bully may be a beast but he's not beastly' trope, if you like.

(Fic about a different Selby, or a what if it had been Peter that Foley gave the lift to, given the Peter--Foley Selby--Anquetil parallel that's sketched here, would be tremendous, by the way.)