Pilots who qualified to "Wings" standard after 1977 (might have been 1978) had to wait until after graduating from an advanced flying training school (AFTS), which explains why some had flown notably more hours than others who were awarded their badge at a basic flying training school (BFTS).
I was at RAF Linton-on-Ouse when the last course to be awarded their flying badges after BFTS graduated. I believe it was 15 Course; I do know that Douglas Bader carried out the presentations. The "carrot" was thereafter whisked further into the far distance. After holding for some months, I didn't personally graduate from AFTS until 1979.