I still believe someone else killed the family, this person rang JB from WHF to tell him the job was done and JB called Mugford first and then the Police - JB could not wait too long as he knew that the calls would be logged, he had to make a delay to allow the killer to escape and he also gained extra time by calling the police station and not 999, driving slowly to WHF.... However the killer was still in the house when they arrived as observed by Bews and JB in the bedroom window. If JB had waited until the bodies were discovered the next day his alibi of the phone call from his Father to implicate Sheila could obviously not have worked. The killer then slipped away only to be seen leaving the area, being described as a scruffy male. The timing is important as there could not be a delay between killing Ralf and calling the Police as JB would have assumed that the doctor would estimate the time of deaths, showing how long Sheila had been dead before the Police arrived - his whole plan revolved around the fact that it was 4 murders and a suicide, the suicide had to look instant - if they waited longer to kill Sheila it would not work as the crucial alibi call from Ralf would require an instant response from JB.... In my opinion this is how it was organised, JB did not kill them, he did not have to return to Goldhanger by bicycle, he was already there since the time he left WFH the evening before. The silencer, mantlepiece scratches etc. were used to frame JB, he had no signs of being in a fight etc. because he did not kill them, it was more convenient for the family and the Police to accuse him while the real killer was never found and probably never will be. I think he told Mugford Mathew did it to avoid identifying the real killer, just in case she did go to the Police, as of course the killer would have brought JB down with him. To this day JB cannot give this information.....he just has to try and discredit the fabricated evidence such as the silencer etc. which is his only hope of release... all this is of course just my opinion.
I initially favoured this view boheme but eventually dismissed it. There were two patrol cars dispatched by Police after two calls which in my opinion were both made by Jeremy to the Police,not to 999 numbers which he thought might have been recorded by the BT operator,but to Chelmsford and Witham Police stations. The nearest Police station was Witham which was 7 miles away from White House Farm so any hitman would have had ample time to scarper before they arrived. I also think the hitman plan was just too risky for Jeremy as he would have had to pay him off for life,and anyway in Jeremy's thinking it wasn't necessary as he knew the layout of the farm and could do the job better than anybody. I think Jeremy sensed a hesitation in Julie and made up the hitman theory to spare her feelings(he was still helping her to move flat even after the argument they had).
The point about the telephone calls was that Jeremy in devising the wording used in the calls limits the suspects to either Sheila or himself-if you believe that Ralph(Nevill) was in the kitchen,unarmed and staying that way whilst Sheila was running amok with a gun around the farmhouse and his two grandchildren asleep upstairs, telephones Jeremy first before the Police then it is Sheila who is the culprit. If you think that there's no physical evidence that Nevill did make the call then you're back to suspecting Jeremy. I think Jeremy tried to keep it as simple as possible,hence the planted gun,the telephones mysteriously going dead after just a few words. I also think that had Jeremy used a hitman he didn't need to be at Goldhanger cottage at all that night-why not arrange to spend the night with a friend in London and just wait by a telephone box every half hour say for a call to come through saying the deed had been done?
I don't quite follow your timing theory because had a hitman been primed by Jeremy about where the rifle was,layout of the farm and so on there didn't need to be a telephone call to the Police at all. Jeremy saw a window of opportunity to commit the murders between the Sunday and the Wednesday,hence his call to Julie "tonight's the night",cynically knowing that it would be his last chance for some time to do away with his family and thus becoming the sole beneficiary of his parents' estate.
