For context the photo is cropped from a wider pic:
View attachment 347214
Looks to me like a training area , probably late in the war, I think he was conscripted, rather than a 1914 volunteer. Bloke top right has a swagger stick and an earlier pic also shows him with the same.
@putteesinmyhands - yeah, entire family came from Swansea, before that Carmarthen. His older brother was Royal Welch. Jack the lad was a bit more of a handful I think
Sergeant also has two wound stripes. Can't see anything that says much more than RA to be honest.