Happy memories indeed, I made it many of the late 70s and early 80s shows and was also involved in the inter-service gliding championships that were held there in - I think - 1979.
One notable participant at those IATs was Major 'Boy' Soons in the RNLAF F-27, whose display was quite incredible.
In its latter years it was starting to get unwieldy and wasn't spectator friendly, with large marquees and flagpoles littering the crowd line.
This is the last time I saw Greenham, just as they started to dig up the runway.