It's good to hear that you only live a few miles distant from the RO just check before you leave that they do have the AVR's and take all the addresses you have.
That is a lovely poem about your ancestor for your archive. Also, you could check again to see if they have any local newspapers that may mention him perhaps coming home being discharged etc at the end of the War. I think that there was a branch of the RAMC stationed at the Army HQ near Aldershot? so sorry I cannot recall the area but I think it is in Hampshire/Surrey. If for example he was the soldier mentioned briefly in the index you may find the hospital. I think it is totally wrong that these men were not equally recognised for their home service as they did such sterling care of soldiers horribly wounded. My F in L was nursed in somewhere in the south of England, with multiple gunshot wounds, but he lived to tell the tale thankfully!
Kind regards,
Pat
p.s.
Have you checked to see if your ancestor had a second name I found at least 4 on the medal rolls in the RAMC but no 'just James' there could be more as I only got up to page 25 at the NA:
Description Medal card of Wright, James Ruben
Corps Regiment No Rank
Royal Army Medical Corps 119165 Private
Date 1914-1920
Catalogue reference WO 372/22
Description Medal card of Wright, James Wilson
Corps Regiment No Rank
Royal Army Medical Corps 113556 Private
Date 1914-1920
Catalogue reference WO 372/22
Description Medal card of Wright, James Alexander
Corps Regiment No Rank
Royal Army Medical Corps 140000 Private
Date 1914-1920
Catalogue reference WO 372/22
Description Medal card of Wright, James H
Corps Regiment No Rank
Royal Army Medical Corps 49535 Private
Date 1914-1920
Catalogue reference WO 372/22
I do wish you luck with your searches just when you draw another blank there is often suddenly a chink of light and I hope you get it. Just keep chipping away at it David.