Slight digression if I may be permitted.
What were the Ground School Instructors' gradings after Ground Instructor Training Course?
I did mine [to teach Met] c. 1970, cannot remember where [Newton? Upwood?] and found it superb ....... later in career I was a senior instructor at the Met Office College, Shinfield Park, and realised how well my brief GIT had prepared me, in contrast to other instructors who were, shall we say, not "teachers" but "lecturers". There is a difference!
I think I was a humble B, and a few Met folk held an A? We were checked by trappers fairly often.
Signed OLD GIT.