There is no evidence the relatives fabricated the silencer. Just your own hand picked sources.
They needed the police to give them Sheila's blood as well as a mountain of other information. Straight away. Your diluted blood theory is a non starter.
More BS from you as usual.
August 7th DC Clarke tells Ann Eaton that Nevills body was found by the AGA near the mantle shelf.
August 8th: Ann Eaton takes Julie to the mortuary and notes down Nevills injuries after talking to Julie.
Jeremy provides a witness statement saying he left the rifle in the kitchen without the silencer on.
August 9th: After visiting the accountant, Jeremy asks Ann Eaton to pay back the loan for the farmland that she is living on. In order to pay death duties.
Ann Eaton visits WHF with DCI and DS Jones. While there she would have seen the blue coat obscuring a certain area of the mantle shelf.
August 10th: Relatives visit WHF again and collected the silencer and also take back home Sheila's blood stained clothing. David Boutflour does not recall seeing any blood, paint or hair on the silencer while at WHF at this stage.
Ann Eaton contacts Whitam police station about the silencer later that evening.
August 13th:Stan Jones collects the silencer and gives it to DI Cook.
August 14th:Ann Eaton alerts DI Cook to the scratch marks under the mantle shelf.
And so, to summarise AE had the means motive and opportunity to contaminate the sound moderator in order to incriminate JB.
They knew Jeremy said he left the rifle out without the silencer on. Thus they could seemingly contradict his statements.
They knew where Nevills body was found.
They knew Nevill had bad facial injuries.
They knew the coat was obscuring an area of the mantle from crime scene photos where they later showed the scratches to the police.
They knew there was a mess in the kitchen.
Thus they could make it seem the silencer was involved in the kitchen altercation.
They knew Sheila was shot under the chin/neck.
They had both Sheila's blood and the silencer in their possession.
They had unlimited access to the crime scene.
Thus they could make it appear she was shot with the silencer attached and a killer put it away.