God, Samson, you are SO patronising. (That means talking down to someone).
Bearing in mind that you've managed to do to IA what Gary Glitter did to babysitting, shall we tackle one point at a time?
Why isn't the gun covered in Sheila's prints?
I have no idea, but that question does not steer us to a certainty that Jeremy was there.
Since you admire my body of work on IA have you read the attempt by MikeG to get Nevill shot in the bedroom?
It doesn't work yet he won't concede.
I start with the plan, here is Jeremy's.
1. I want money now.
2. I will ride to the farm and shoot them all, and then persuade Sheila to lie down and be shot in a suicide compatible trajectory. She will be compliant because she knows if she resists I will just shoot her. Though this means either way she will realise she ends up dead, she is a bit gaga and won't object.
3. I will call home, then jump out the kitchen window, bang it shut so the latch drops, create a locked room murder mystery.
4. I will ride home and store the clothing to get rid of later in my own time. Despite the 5 corpses no one will suspect me so no worries about being found with forensic evidence.
What could possibly go wrong?
In my view this is the most preposterous nonsense, yet this is the crown theory.
The funny thing is when Mark Lundy allegedly did something similar, his car and belongings were immediately confiscated, in pursuit of evidence. None was found because he didn't do it. In a similar fashion, Jeremy would have expected his cottage to be a crime scene from the get go IF HE PLANNED THIS. if he did it he would seriously expect to be a suspect. You kill 5 people in a hare brained plan needing luck skill and compliance and seriously expect no one to suspect you? This is driving me demented trying to unravel the logic here that seems to work for you guilters.
If the bike was the only means of locomotion seize it get the dogs on the bike trail and so on. You have the plods being complete idiots.