You obviously followed me by a few months HD. I did my APC/RAD in the spring of 71. At that time the for initial practical training on the Sim for some reason there was no simulated D/F. As a result the blip drivers would end every call with a QDM until such time as the student advised them that they were identified. Come the day for our first "live" runs we trooped over to the tower and I was detailed to take the first slot in the Dove. Off we went round the back of the Isle of Wight where we we were transferred to the student frequency. The conversation went somewhat as follows :-
"Radar this is GALFU."
"GALFU Radar what is your QDM?"
"Radar GFU, Say again!"
"GFU Radar what is your QDM?"
All this not helped by the fact my colleague was an overseas student with a fairly pronounced accent. At this point the pilot turned to me and somewhat pointedly said, "I thought he was supposed to tell me that!" I can only imagine the frantic pointing at the D/F display that was taking place down below.