The double headers on the Fawley / Salfords were late 70's, early 80's, also at this time were double headed 33's on the stone trains from the west to Ardingly, which could be seen @ Haywards Heath, Brighton crews took over these turns @ Chichester, ran to Hove (later Preston Park) for relief then to Ardingly and back and to Havant for relief.
The heaviness of the train from a standing start, made to Cliftonville curve difficult so the crew swap was moved from Hove to Preston Park.
As to a 31/37 combination, or anything else 'different' sorry no.
Most months there were Football Specials to Hove but 99% of these were 33's worked south by Norwood men, we would take over @ Hove, run them down to Littlehampton, wait a couple of hours then take them back to Norwood men @ Hove.