Not that I necessarily condone this thread and its speculation, but I'm going to try and assist the OP by clarifying what I think he (or she?) is driving at.
I think what is being said here can be reduced to this:
(i). If we adopt the hypothetical that Sheila did this, there is a further possibility that Sheila had assistance that Nevill did not surmise or detect before he made the call to Jeremy.
(ii). This assistance could have come from Jeremy of course, but what's being suggested is the possibility it came from a third party instead of (or maybe even in addition to) Jeremy.
(iii). One avenue (among many) this leads us to explore is to ask who else Sheila had associations with.
(iv). To be honest, Colin Caffell is not the first person that springs to mind, for a number of reasons. He has to be the most unlikely suspect. I'd suspect Crispy of wrong-doing before him.
But let's ask the question anyway:
Does Colin Caffell have a solid alibi for that night? If he does, then unless he had astonishing powers of suggestion, he has to be excluded.
On the other hand, if he has no alibi, then this does not imply he had anything to do with it, but it may be fair to ask what was he doing that night.
My understanding is that the police never made inquiries of him. No doubt this is partly because they found him at his house in London, and (I assume) his then-girlfriend will verify that he was there that night, if she was living with him.
Another, more neutral, way of posing the question would be this:
1. If we assume a hypothetical in which Sheila did this, do we also accept that Sheila had to have acted alone or did she need assistance?
2. If she needed assistance, are we saying it had to be Jeremy (so Jeremy is guilty anyway)?
3. If we are excluding Jeremy, then who else is in the picture?
I hope that captures it. Again, I don't condone this line of speculation necessarily. Please don't attack the messenger, I'm just assisting the OP by trying to bring clarity to things and set out some parameters.
