This could be his medal index card - on Ancestry:
https://www.ancestry.co.uk/imageview...ce&pId=4193820
and on TNA (will be free on there if you sign into your account):
https://discovery.nationalarchives.g...ils/r/D2918428
Private, no 9423, in the Argyll and Sutherland Highlanders. It doesn't show his middle name though so I can't be sure it's the right person. (The 1921 census doesn't show his middle name either but it says born Govan so I am sure that one's him.)