Wow! You guys are QUICK! Thanks for all the help.
I don't seem to be able to get to the info even when you've supplied the links. I found an EJ Oliver listed in Carole's FBMD link but he was listed as Tynemouth - then I found him in Plymouth - I've no idea how?! Doh!
Anyway, back to the story. I think the EJ Oliver is the one born in Cheltenham. The War Graves Commission shows him living in Plymouth but his wife came from Cheltenham. Also he is on the Royal Engineers 'Cheltonian' Roll of Honour so he either joined there or was based there. And this explains how he married someone from Cheltenham.
Actually, looking at the CWGC certificate again I suppose it makes more sense to read it that HE was a native of Cheltenham, not his wife, although it's a little ambiguous.
If this is right his father is listed as John Jnr. Oliver [was Junior a name in those days?]. John Jnr was born in Silverton which is about 8 miles N of Exeter so that may help explain how they ended up in Plymouth?