This has turned into a very interesting thread which hopefully will be resolved at some point, I guess the only person that can shed some light onto the question will be the man himself, if it is him, what was he doing flying a HAS2 and when was it.
But one of the aircrew on this thread has already said that they don't think it was HRH in the LH seat. I guess does anyone know if John Skinner is around to shed some light on this?