Another thing...
I am not convinced that the telephone used by Neville Bamber to call Jeremy and then the police was the kitchen phone (as depicted in the crime scene photographs)! We know that a request was made for DC Harris to call ACC Peter Simpson using the land line at the farmhouse because its documented in one of the police logs...
We know that Harris, Gibbons, and Montgomery, entered the kitchen just after the three other bodies had been reportedly found upstairs, which when added to the two bodies already found downstairs made five dead in total by 8.10am...
We also know (highly significant) that the 999 eavesdrop set up by the operator was terminated at precisely 7.47am (just after 'Linda' in the control room contacted (SOCO) DS Davidson (7.45am) at his home addresss, to request that he come on duty into the office because police were dealing with an incident at whf, involving 'a murder, and a suicide'. Why was the landline eavesdrop stopped so soon after 'Linda' had spoken with DS Davidson about the discovery of two bodies downstairs in the kitchen by 7.45am?