Your best bet is to go to forces records for the UK. The site is compiling all military records, I must say though the site is still uploading records and the record you need might not be digitised yet. If it's not there then if you know his unit you can contact the relevant museum in the UK or M.O.D. (Ministry of Defence is the Umbrella name for all armed forces in the UK) Also we have links to the museums, etc on the following WikiTree pages.