Why did Sheila stalk Nevill and wait for him to realise the other had been shot Mike ?
Adam, I am as convinced as I can be, that Neville Bamber was not present inside the farmhouse when June and her two grandchildren were shot to bits, and killed...
In this narrative, Sheila would have easily been able to dispatch her two young sons, and her adoptive mother..
If Sheila was the shooter, that just left her to deal with Neville Bamber, which was a different proposition, altogether...
She had to set a trap, and wait for Neville not only to return to the farmhouse at around midnight, or later, but she had to make sure that whenever he stumbled upon her handy work, that he could not raise the alarm immediately! In this respect, I believe that Sheila unplugged the bedroom telephone as part of her strategy, so that when Neville discovered the awful truth that he could not raise the alarm from the main bedroom, but that he would need to either go to the upstairs office, or downstairs to the kitchen to alert, Jeremy and the police...
One thing looks a certainty and that was that in order to discover the awful truth concerning the loss of life in the case of his wife (June) and his two grandchildren (Daniel and Nicholas), Neville had to be upstairs in either bedroom, and that the shooter lay in wait for him at that time, to make his way toward one or the other two phone points in the farmhouse (upstairs office or kitchen). All Sheila had to do was conceal herself behind her own bedroom door, or the latched door at the top of the spiral stair case, and wait for the moment that Neville came back out onto the top landing from the main bedroom!
Of course, timing would have played a vital role in whether or not Neville was able to avoid or escape the interest of the shooter, and based on what is now known it appears that Neville was provisionally successful in making his way all the way down to the kitchen, arguably only being shot once on his way down the main stairs!
Once downstairs in the kitchen, and with Neville alerting Jeremy and the police by 3.26am, it then became an issue of an armed Sheila versus a wounded Neville Bamber - I don't buy into the claim that there was any struggle between Sheila and Neville over the possession of the loaded .22 anshuzt rifle. This is because, any struggle that took place in the kitchen invariably involved a fight over the possession of the 12 bore shotgun, which scratched the kitchen mantelpiece...
Exactly when such a struggle took place, is another issue..