Thanks so much for checking the index cards Ady, as I don't know when he enlisted it's a bit difficult to take a guess at which one of those might be him. He was born in Sep 1899 so possible the 1916 one, but still he would surely have had to fib about his age on enlistment? Mind you, I don't think that was unusual!
Jebber, thanks for the link. I'll definitely take a good look on the site and contact them, hopefully they will be able to help me track down his regiment number.
muvva