It's interesting that guilters are the ones who rely on this extremely complex theory that requires Jeremy to somehow sneak out of his own house in the middle of the night, enter a farmhouse undetected, kill his entire family - including two small boys - which involves his father running down the stairs after being shot four times, leaving hardly any blood while he runs round the house. Jeremy leaves the farmhouse with no forensic traces of his presence, then makes it back to his own house in quick order so he can make a call to the police (in effect, reporting his own crime to the authorities) - making sure not to be seen around Goldhanger when he does this. Oh, and he leaves incriminating evidence behind for hostile family members to find, turning down an offer of the house keys from the police. And he tells his girlfriend that he did it. Then he breaks up with her.
And his motive is money. He kills his entire family for money, including two little boys. For money. Just stop and think about it for a minute. Go for a lie down in a dark room and consider it.
And don't forget: he went by push bike! I don't normally, but I think I'm entitled to 'LOL'.
The straight-forward scenario is Sheila did it.
The more complex scenario involves Jeremy.