I do agree on police cover ups and I do believe that back then once the senior police officer is focused on one line of investigation it's hard to move his stance, take Oldfield in the Ripper investigation he was gone on the geordie accent, even though other officers was telling him to dismiss this theory and if he had listened it could have saved others.
But what are we led to believe about the cover up, was it one person and the family (impossible) was it a few senior police and the family, was it every police officer who said anything negative about Bamber, was it Julie Mugford, was it forensics or M15 coupled with Free Masons or was it drug related. Did Sheila lay on the floor and pretend to be dead in the kitchen then jump up and run upstairs and shoot herself, or did the police shoot her in the kitchen then upstairs again by accident then cover up their own mistake and blame Bamber. Or was it simply a mistake by the police who were led to believe it was murder suicide and were led by someone like Oldfield who didn't like being proved wrong and made assumptions before forensics and lines of enquiry had finished? I do believe the killer, like the Ripper and Bamber, were staring the police in the face.
I think you make some good points here.
I think a small group of officers were 'sympathetic' to the relatives and undermined DCI Jones. This did not initially contain Miller - as he expressed "disgust" at the relatives insinuations. Didn't Stan Jones also initially challenge Ann Eaton, regarding the prospect of 'sending an innocent man to prison'?
Once the pressures to investigate Bamber were created by ACC Simpson - officers simply jumped ship to what was required. Some stayed silent - others actively took part (perhaps this speaks volumes about individual characters and their levels of integrity - or lack of it).
Why Simpson decided to change? Perhaps if EP
retain control of the case - it gives them the opportunity to continue to cover what happened in the farmhouse and allows them control over the available original evidence. They have a window of opportunity to manipulate and hide evidence. Once relatives go to press or a higher body than EP top brass, external queries could be directed towards EP. There would have have been the spectre of an outside agency or police force discovering the original evidence - bringing in to question all of the orginal decisions made by Simpson, Harris, Jones etc.?
I think this is where the suggestion comes from - that EP probably wanted the prosecution to fail - while simultaneously appeasing the relatives - that everything possible was done to achieve a conviction.
I also find it intereting about what you suggest may have happened with Sheila. I once suggested that and a former member (current member of red forum) described my scenario mockingly as 'Sheila playing possum'. I've wondered about it because it aids in the defence suggestion she made her way upstairs. It does not explain though, how or why police regarded her as "dead" and a "suicide" on entry to the kitchen - as she would in this scenaio have no obvious wounds.