Thank you all for your help, had been looking at the National Archives web site, but must have been searching in the wrong spot and didn't find that information. Yes the uniforms and facial hair of the RNAV's bear a striking resemblance, have photos of my grandfather about the same age and his moustache is a thing of great glory as well. Have heard that FindMyPast has free Military records 24-27 May so if I can't get to the library before then will search for his records then.
Had the power off today while the Meter board was replaced and delved into the depths of my late Aunties large, heavy suitcase of mostly unnamed family photos and hiding at the bottom was a letter, dating from the ages given about 1942, plus NAMED photos of James and his family taken in England before and during the Second world war, from Jame's daughter who was born about 1921. So yes it would be him died 1951 in Harrow. Yesterday I knew not a lot about his family, thanks to my Aunt the "hoarder", now have a whole family and some spouses to add.
Cheers
HeatherR