We have all written scenarios at one time or another. However, your scenario on how Jeremy committed the crimes is as valuable as NOT writing one about how Sheila committed the murders because WE WEREN'T THERE!! The argument is that Sheila wouldn't have been strong enough being a small weak frail female. That's bollox - she was bigger than me and I don't think I would have any problem overpowering a wounded 61 year old male with a chronic back problem - if I ever needed to and ESPECIALLY if I had a rifle in my hand!!. Never fired one but it certainly doesn't look like rocket science ESPECIALLY for a farmers daughter who had been brought up around guns!!
There are lots of other things that need to be fitted into a Sheila scenario.
When did Neville make his 'mysterious' phone call to Jeremy or the police ?
How did she re load twice if she had no experience with guns ?
When did she reload twice ?
How could she do this if, as AE said she was so uncordinated ?
How did Sheila shoot herself twice ?
Why did Sheila put the silencer away ?
How did Sheila manage to do most of this between 3.26am - 3.48am ?
Why would Sheila be so keen to stop Neville making a phone call ?
Who pulled Sheila's legs after the second shot ?
Why did Sheila apparently shower after the murders ?
Why was there no gun residue on Sheila. After firing 26 shots & at least two after showering ?
The 14 points from Mumsnet.
Why was she in the corner of the bedroom with the mother she did not get along with. The father and children she was attached to, discarded ?
How did Sheila's blood get on the silencer ?
How did Sheila not have any marks after a fight with her father ?
Oh, and how could Sheila give Neville such a beating ? Breaking a bit of the rifle in the process. BW said Neville could control her with one arm.