Roadster, the clue in my post was Henlow. In 61 Cranwell was exclusively aircrew and mostly pilot at that. Cranwell was essential if you expected promotion to sqn ldr and beyond. It was possible to be promoted to sqn ldr whilst on the Supplementary List with the bonus that passing the C was not required. However for promotion to flt lt it was essential that one passed the B. It was noit unusual to find fg off with 12 years seniority in rank. They enjoyed the almost total lack of power or authority.