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.
The known facts are that its a HAS2, it has the code 91 on the nose, the code is painted black so the photo was taken after March 1982, there is no record of a Sea King going south with the code 91, after post Falklands leave the squadron re-embarked and went west to the US, so why was HRH at the controls of a HAS2 and when?
Interesting indeed