Back in the mid-70s I was holding at a non-flying station in West London where the rugby was quite good. I was lucky enough to play for the Station and RAF Support Command. Outside me was a Cpl PTI who was really quite useful and not slow, but who couldn't pass his Sergeants Exams for love nor money. All this and playing for a well known London Club, one of the Home nations and also the British Lions. Don't think
the system works all the time.
jf