Thanks QC that was a interesting read.
I have a couple of questions:
The bullet cases in the master bedroom/kitchen do not match with your scenario?
Also I was thinking about the dog, it would have made a racket as JB came in through the window and especially as soon as the first shot was fired?
I also think it unlikely Sheila would have slept with June just to be a few feet nearer the twins?
The location of the spent cartridges cannot be relied on as they could have easily been moved around by police officers marching all over the crime scene in thick-tread boots.
Bruce was in the yard and I think he was open-kennelled. He probably barked initially, but on recognising Jeremy (by scent), he would have quickly stopped.
Crispy was asleep downstairs, I believe, but you will see that my scenario has Nevill alerted by the noise of Jeremy's entry into the farmhouse. There are two further points to consider, though. First, Jeremy had a habit of entering the farmhouse in this manner, and probably Crispy would have recognised him. Second, it also depends on which window Jeremy used. There is the kitchen window, but knowing about Crispy and the stuff on the sink top, Jeremy may have decided to enter via the downstairs shower/WC window. This would presumably have the advantage that the shower/WC door was closed, so any noise was less likely to alert Nevill, if he were downstairs.
It has occurred to me that Jeremy may have anticipated that Nevill would be asleep downstairs or sitting in the lounge, even at a late hour, so I have edited my scenario to allow for this by adding a section at the end.
I agree it would be odd for a 28 year old son to sleep in the same bed as his mother and father, but Sheila was a woman, so it's a bit different, and remember she was severely mentally-ill and had all sorts of 'issues'. In a sense, her parents were still her carers. She may have found it easier to be in the main bedroom to access the twins, especially if the twins also had a habit of walking into the main bedroom through the box room. I know from experience that small boys will often want maternal comfort at night and/or in the morning and will climb into bed with 'Mummy' or 'Granny'.
The main reason I posit Sheila sleeping in Nevill's place is because it very much fits the evidence and explains an issue I have with the prosecution case, which is why Jeremy would position Sheila in the main bedroom rather than with the twins. And apart from what Jeremy would plan to do, wouldn't a threatened Sheila run towards the twins instinctively and end up with them anyway?
To my mind, it only makes sense if we say that:
(i). Sheila was shot in her own bedroom or the main bedroom without transiting from one to the other; and,
(ii). Sheila was caught in a position where Jeremy could very quickly pull her off the bed and pin her to the floor.
That points to Sheila sleeping in Nevill's place. I think all the evidence: blood, pathological, ballistic, is consistent with this possibility. I only say it is a possibility, and I do not say it is without problems, though it seems the problem is psychological-behavioural, not strictly forensic: i.e. why Sheila would sleep in the main bed, isn't that odd, etc.