My friend, I fear you are in danger of wrapping yourself up in an ever decreasing spiral of trying to make information fit whatever it is you want to prove.
My concern is that is what the BoI and H-C appear to have done. By the way I did spend several years involved in investigative aeronautical engineering, and in my book, the "Blow-off" and gasses coming into the bomb bay theory does not fit. I can not speak for the experience of the BoI members and H-C in that field.
The photgraphic evidence, not mentioned by BoI or H-C, clearly indicates that in the case of XV227 the hot gasses did not flow from Dry Bay No.7 to the bomb bay, therefore, on the balance of probability it is unlikely to have happened with XV230. The "blow-off" was not seen by the tanker crew, and the theory rejected by the coroner, not just me.
Finally, an Air Incident report, involving AAR of XV260 on 8th Nov 2006, provides the evidence that the tanker crew could see venting and "blow-off" (if they took place). This report gets no mention by the BoI or H-C, probably because it does not fit
"what they wanted to prove"
DV