Hi Rita,
and a Happy New Year to you too !.

I'm pleased your William got home safely from WW1 and lived a good time afterwards. However as I suspect you've realised this is almost a "disadvantage" when researching his War, as the most-easily-found records seem to find those who died rather than survived eg Memorials, Honour Rolls and newspaper accounts( eg Laura Morse Diary). Similarly this forum understandably contains posts about those who died, or were wounded, but less so the much more numerous survivors. As you know the best WW1 sources are the Service and/or Pension Records, rather than Medal Cards, as these Records contain details of next of kin, home address etc. What an ironic shame that most of these records were destroyed during WW2, unlike the far more common Medal Cards. However there are other possible routes, with local newspapers always being a good start, I have an interest(and past career) in all things Military history, so I always look out for military ancestors.
eg like you I struggled to find one of mine amongst several Medal Card "possibles" until I saw his 1915 Marriage Record within this great website, it told me he was a Corporal in the Monmouthshires so very helpfull indeed, he died in 1945 aged just 56, so a contemporary of your William perhaps.

When searching Ancestry etc for Service and/or Pension Records for WW1, I recommend always searching "outside of the box" even with apparently straightforward names. I read thro ALL the Records that MIGHT POSSIBLY be my target, as I've found sometimes what is claimed to be a 10page record for one man is actually two shorter records for two different men; also sometimes the record pages are accidentally mis-filed, there's a chance your man's records may be there despite the search engines initially suggesting otherwise.

My father and other family ancestors were from Lydbrook, so I have also searched Ancestry's WW1 Records using placenames including "Lydbrook" as key search words, very helpfull in my case when searching VERY common surnames such as Aston & Jones - this way I've found soldiers who turnout to be relatives that hadn't previously been on my already quite far-reaching trees. I also kept records of those outside my tree from other Forest towns, with the intention of posting on this forum, - however five months ago I had a serious virus infection that deleted many hundreds of pages of text documents, photos etc etc containing all my FH researches including those on my standalone "safe" backup drive, so sadly I cannot check those for your William.

Just occasionally soldiers are named within Army Unit diaries, but only on rare occasions such as during acts of extreme bravery, but still maybe worth searching if possible. You may know the National Archives have just(this week) started placing digitised War Diary Records on their website, but this will take some years to finish.
http://www.whodoyouthinkyouaremagazine.com/news/first-world-war-unit-diaries-go-digital...

I've just found your great photo of William, I think you're very lucky in having a photo of him in uniform, and even better not the more usual studio photo.
Have you tried getting the original photo, or a high resolution scan of it, examined by a miltary uniform expert - the cap badges look particularly prominent for example ?.
http://www.forest-of-dean.net/gallery/lydbrook_2/mediafiles/l27.jpg

On that subject, I don't think the capbadge in the photo is the RAMC, it seems too wide/heavy to my eyes altho you have the original photo. These sites may help;
http://www.ww1photos.com/RAMC.html
http://www.ramc-ww1.com/index.html
That said, of course badges do occasionally change slightly(for ease of manufacturing) during the course of the war, plus soldiers could be transferred between Regiments, so ??

You could also try posting the photo onto Military history forums, I've found these to be extremely helpful. You may even find someone who knows the other men on the photo !. One of the best if not THE best WW1 sites is the Long Long Trail, as you've probably already found. Military history is a very popular interest and there are incredibly informative sites and very helpfull forums about what may seem the most obscure subjects.
http://www.1914-1918.net/soldiers/research.html

Hopefully this will help you, good luck, Jeff.

This is quite a timely query as The Trust is soon to upload a database of Forest of Dean Soldiers that has been compiled from a number of sources including enrollment lists from the Dean Forest Mercury. The data is still being compiled and updated and though by know means complete it will be an interesting database, along the lines perhaps of the one proposed by the Imperial War Museum http://www.livesofthefirstworldwar.org/ but just for the Forest Of Dean

A quick look at my data shows that we have 64 James' listed though no William H James but he may still be amongst those recorded in the Mercury that have not been checked yet, so please keep a look out for the data when it uploaded as he may be listed by then

The photo doesn't contain enough detail to be sure but the cap badge could easily be the Gloucestershire Regiment. It's the right kind of shape and you can imagine the sphinx at the top of it. I have my own grandfather's in front of me at the moment. It's a pity there's no chance of seeing a back badge to confirm it. I wonder if I'm just seeing what I would like to see!

Rita, this is off topic, but have I ever asked you whether some of your James mob settled in Woodend, North Canterbury? The James family used to own a farm near the Woodend pub. They converted the farm into a subdivision that we lived in until recently. The main reason I ask is that one of the lanes in the subdivision is called Lydney Lane.

The widow of one of the sons, Errol James, still lives in the subdivision and I could put you in touch if you think there is a connection.