MReyn,
Sorry, I had missed your second post. I will pass that snippet back to my father.
I guess what I was after was finding someone who has a personal special interest in the original Instone. Given the pioneering nature of what they were doing, and also that they were a foundation stone of Imperial/BOAC/BA I was expecting/hoping that someone here would be a keen historian specialising in them.
However I have also spoken to a friend, David Edgerton, who is Professor of Aviation History at Imperial College, and he doesn't know anyone specialising in that period either.