Most of us were recoursed off our basic nav course after 4 weeks. Not because we were no good but because the students ahead of us were too good and too many passed and could not go on to the advanced nav course.
Believe it or not, that was true.
Equally I am probably still alive because of it. About 2-3 were not recoursed and the one who went straight through a month ahead of me was on the Vulcan that crashed at Coningsby.