What I have to say below proves something but I leave it to others to decide.
Of seven nav studes 5 were chopped pilots, two had the preliminary flying badge. Six were ex-UAS. Two wanted to be navs not pilots.
Guess who got the preliminary flying badges.
Guess who graduated as navigators; one made Buccs, one made GR1s.
One ex-UAS, failed PF, chopped BFTS, made it through to Canberras.