I went to OASC two Januaries in succession. The first was for an RAF Flying Scholarship, so just a day. The second was for FAA aircrew aptitude tests, so again just one day.
I remember the fruit machine test Columns of symbols moving downwards through a panel, with a panel at the bottom with changing symbols - the objective was to hit the button when the panels matched. There was also a delayed-reaction (controls inverted?) keep the dot in the middle and that's about all I remember. 1977/8 is a while ago.