Let me know if I missed any grounds.
You haven't properly addressed the Aga burns, Adam!
You know darned well they have nothing to do with Nevill being found on the chair/scuttle!
If it was proven in 1985/6 that the Aga did indeed burn Nevills back [for three+hrs?] this would have a profound effect on the police scenario sent to the DPP.
In fact it would demolish the police scenario which has Nevill chased to the kitchen and killed minutes later.
Deep down, you know the Aga evidence is a big problem for those who think JB is guilty, Adam?
BUT!!! JB and his team must forget about the possibility that the police moved Nevill after entry!!