Hi Malcolm,
Here are two or three possibilities for you to follow:
1. If your grandfather was absorbed into the RAF from the RFC in April 1918 then his service record should be available in the file series Air 79 at the National Archives at Kew. It requires a personal visit to check it out, but the staff there are very helpful.
2. If he stayed in the Army rather than the RAF it becomes more difficult. This is because around 80% of Army 'other ranks' service records from WW1 were destroyed by German bombing in WW2! (We repaid them though, by - sadly - doing the same to most of their Jasta archives later on in WW2).
Those records that survive are known at Kew as the 'burnt records' as many are somewhat singed. I don't have the series number to hand, but Kew have details in their many handouts, or on their website.
3. A last resort is to search the Medal Index Cards on-line at the National Archives website. If you find the right card you can download it for £3.50. Or you can visit and search for it by hand for free. The web address is:
http://www.nationalarchives.gov.uk/documentsonline/. BUT, the medal index cards do not contain very much information at all: simply the name, rank, number, corps served in, medal entitlements, and (sometimes) the theatre of war e.g. France, Palestine, etc.
Hope that's of some use, and very best of luck.
Bob
__________________
Testerchild
Remembering:
Driver T2/10816 G Tester, born Kirkcaldy, Fifeshire: A.S.C. & Aerial Gunner 20 Squadron RFC - my maternal grandfather: Killed in aerial combat 28.09.1917: Pont du Hem Military Cemetery, France.
Able Seaman J McCullagh, born Co. Wicklow, Ireland: my Great Uncle: Killed in action, SS Mavisbrook, 17th May 1918.
Captain R A Sellwood, born London: 44th Bn C.E.F. - My paternal Grandfather - Survived
The Union Flag runs in my veins.
HTTP://www.winged-sabres.com