My paternal grandad joined the RA (155bty, 52nd L.A.A.regiment (TA)) in 1937 because his elder brother (who had been in for a few years) said that they had a good snooker table! Only a short war - he left home in September 1939 for France and was back home (in a hospital bed!) by the time that Op Dynamo ended, gaining his discharge due to his severe head injuries. He spent the remainder of the war ,well, 1941 onwards(after a recovery as good as could be expected) as a civilian security guard at some military installation near Birmingham. His brother went on to fight in N.Africa and the Far East and had quite a few eye-opening tales to tell!.
My maternal grandad was conscripted into the RA in 1940 and fought in N.Africa and then Italy (transferring here to the Lancashire Fusiliers and then ending the war with the Loyals). The first in my family to be cremated (after death, of course!

) due to his fear of being buried after his experiences in an Italian cemetery under bombardment!
Maternal grandma was in the ATS, but I know nothing of her (and probably never will), and my paternal grandma (after the return of my grandad) probably spent the remainder of the war developing into the bitter, twisted old hag that she was to become later!
Dave