Abbreviations etc
Danny42C - having looked up your encounter with Sir Basil Embry and mindful of my own experience re questions on Rugby Football, I did often feel that its supposed mystique had undue influence on certain elements of the RAF hierarchy; in fact the game was often responsible for rendering some of its more enthusiastic followers unfit for duty through injury, with the result that others had to then do their jobs for them - sometimes at personal inconvenience, not to mention any to the RAF (plus loss to the taxpayer for hospitalization etc).
The two routes available to prospective pilots & navs, so far as I recall, were either the usual one by volunteering directly for aircrew, or the University Air Squadron scheme whereby one spent six months at selected Univs covering the ITW syllabus plus an academic subject of choice; at the end, a few weeks was spent square-bashing at ITW before proceeding to Grading School. This system had the advantage, for those who might have wanted in the normal course of events to go to Univ, that it got your name on the college/University books and thus secured the right to go back there after the war if one so desired.
As for abbreviations: AFU & OTU are I think well known, TSCU stood for Transport Support Conversion Unit, GPU for Glider Pick-up Unit