I submit that the best, most plausible, defence theory is the original one.
At the trial, Jeremy's lawyers accepted the evidence that the sound moderator was used in the killings and that blood in the moderator was victim(s) of the shootings, but as the experts allowed a possibility (albeit a remote one) that the blood could be an intimate mixture of the parents, so Sheila could have shot the other family members with the sound moderator on and then removed it to kill herself.
Rivlin QC demonstrated that the time of Jeremy's call to the local police was 3:25 - not 3:36 as noted on a log - which allowed the possibility that he called Julie Mugford around 3:30 after the call to the police.
The defence against the Crown argument thats, e.g. Sheila did not have broken nails was these kinds of arguments were not conclusive either.
The defence only accused Julie Mugford of lying (plus a few others who said that Jeremy talked about killing his parents), which was quite sensible, rather than accusing half of Essex of lying as the Campaign Team do.
*********************
The reason why this theory has to be abandoned is because they need "new evidence" and new theories like "rabbits blood" or "Sheila's menstrual blood from her knickers" or accusing the police of framing Jeremy (despite the lack of evidence). With new evidence there can be no appeal.
1. This would mean Sheila attached the silencer on the gun
2. Shot June and Neville.
3. June and Nevills blood then ends up in the silencer despite not suffering contact wounds
4. Sheila and Nevill have an altercation while Neville can only use one arm. (One arm having a comminuted facture)
5. The altercation causes scratch marks behind a hung up jacket and does not fall down.
6. Sheila then removes the silencer before shooting the twins and herself.
7. The blood in the silencer then gets misinterpreted.
8. The relatives find the silencer with blood and paint on but hold onto it for three days instead of taking it to the police straight away.
The list can go on.