Does anyone recognise this button?
It is brass, 24 mm.
I doubt that any hospital in Wales was ever named "Welsh Hospital". An internet search yields a "Welsh Hospital" in South Africa during the Boer War:
It is mentioned in this wikipedia article:
https://en.wikipedia.org/wiki/Spring..._Springfontein
This link has a brief history (South African Military History Society):
http://samilitaryhistory.org/vol123sw.html
And a link to Boer War hospitals in South Africa:
https://www.angloboerwar.com/other-i...=1&limitstart=
Its backmark is one of at least 7 anonymous designs. My code name is 'hammer key' and I think it is associated with Firmin.