It would be informative to see how JB's early recollections fit into the picture as more evidence became known about and disclosed. Did JB's recollections have to change to accommodate new evidence or was it just the prosecution case that required "editing"?
When Herbert Leon Mcdonnell got back to Jeremy in 1992 concluding that Sheila was murdered. Jeremy for a while began thinking it was Anthony Pargheter that murdered the family.
Here is my take
1. A guilty Jeremy would not seekout the help of Herbert Leon Mcdonnell. Who was then seen as the best bloodspatter analyst in the world. (For obvious reasons)
2. A guilty Jeremy would not deviate from what he so convincingly staged.
Jeremy was taken in by what was being told to him. Its worth noting that in 2009 Herbert Leon Mcdonnell recanted his 1992 conclusions and now believes it was a suicide.