I think that as he served into the 1930s his service file will still be with the Army. His current next of kin can apply to the Army and ask for a copy of his records. There is a charge (it was £30 a little while back) but if you go down that route (and it works) you may well find the answer to some of your questions probably more quickly than digging around on so many awards etc!
Also - while there are many helpful experts on here - there is a chap on the Great War Forum who specialises in the Rifle Brigade. I think he looks in here too, but maybe not as often. Might be worth posting there and quoting 'Rifle Brigade' in the post heading.
Bernard