Many of the gallantry awards made during WW2 appear in the Gazette in long lists of personnel with one generic citation to the effect that the award has been made for "gallantry in air operations over a sustained period" - or words to that effect. The implication is that they were awarded at the end of a tour.
The recommendations for these awards are in large numbers of files in the National Archives. The only time I tried looking for one I didn't find the chap I was looking for, but did find someone else in whom I was interested - serendipity is a much-underrated search tool!
In the early 1980s I did an evening class in family history; it was explained to us that finding a birth/marriage/death certificate involved searching through large, heavy index books - one per quarter for each type of certificate - and one of the other students expressed surprise that it wasn't all on a computer. I laughed my socks off - why would the Government pay for the data transfer? Now we have several online genealogy firms who have invested in that work, as well as a crowd-sourced free site, so perhaps HH has identified a gap in the market...