I suspect we will never get the correct info! Just to add to the confusion, PJ Colman adds a footnote to his 1978 articles to say that he got some of his info from Dennis Commins!!!
Incidentally, I found that some of John Knibbs info concerning the BSA Martini model 12/15 did not agree with a model I bought.

Does not matter as long as you are happy with your BSA and I remain a fan of my old BSA rifles whatever their history.

Mike95