kilwhang,
when the RAF finally made up its mind to put the ad hoc AQM (later ALM) trade on a proper NCO Aircrew footing it needed a categorisation scheme. And of course you needed people to run it. Andy was one of those along with a few others. This lasted for a few years until the AQM branch took over the categorisation business and a few were commissioned.
I well remember on my Hastings course Andy doing an airdrop check on one of the instructors from the safety of the flight deck !