When I joined 72 we had a crewman who did a lot of civilian flying to get his PPL. He eventually left the air force and went onto be an airline pilot retiring finally having flown Concorde. But of course we couldn't be pilots as we were only NCO's and didn't have the right qualities.
I’m not sure I entirely follow your logic.., did you go to Biggin Hill having applied to be a pilot only to be told, ‘sorry dear boy, you didn’t go to Eton/ Harrow/ ANOther public school, you can’t be a pilot, you have to be NCO aircrew’? Or did you apply to be NCO aircrew initially?
On the squadrons I served on ex-public school boys were a rarity, almost all were state school educated, not that it really mattered. So the point is that personal qualities mattered more than background. Obviously the RAF used to have NCO aircrew pilots, but I don’t think they were considered to be lesser beings as many were commissioned later, but in those days a person’s background was considered more relevant as to whether they were commissioned from the start.