‘they’ decided to give it to a wg cdr who was about to leave the RAF on retirement.
It was a crazy system. There were so few "allocated"; all Stn Cdrs and (I think) Sqn Cdrs got one, but - almost by definition - they were older and so sooner to leave. Stations had a (small) allocation, many indeed gave them to OCs Wgs.
The only "sensible" rule IIRC was that Sqn Standard Bearers at Finningley for the Review got one. To (try and!) be fair, this was in the medal drought of the Cold War, when many VSOs had nothing sitting below their wings.
Still anomalies with QGJM and QDJM; "J" Class reservists (Uniformed ROs) didn't get one. Amusingly I fought (and lost) a battle for a QGJM for a uniformed RO working for me at the time; 10 years later I was one myself and didn't get the QDJM! The official answer was that "J Class reservists are Civil Servants - Civil Servants don't get the medal - too expensive to give 'em all one".
Between those two Jubilees, I had a job connected with Buck House and heard a good "dit" about the QGJM. Apparently HM wanted to give them to members of the Household, and was given the same answer. So she paid for them herself and all her staff got one! Gawd Bless 'Er!
Apologies for thread drift and congrats to Nikki T.