Researching Cyril Arthur Clarke 3975834

Hello, I wondered if anyone could help - I am trying to trace my Grandfather Cyril Arthur Clarke - he was born in Kirkee, India on 18 June 1911. I applied for his service records and they state he was a Mechanical Engineer before he re-enlisted under the Terms of the War Office on 26 April 1946. Discharged on 12 Feb 1948. Previously he was in the Welsh Regiment? He has Attestion Papers from 1941 that say from 1926-1940 served AFI Poona and Bombay enlisted 3 Jan 1941 Welch Reg. On the 1951 Attestion Paper it says he was in the RAOC and he qualified as a specialist GSC and authorised to have this symbol against his name (can anyone explain what that means??)
He died 17/12/1963 as a Sergeant Royal Army Ordnance Corps - still serving??

Any help really would be gratefully received I'm afraid he died before I was born and my Dad died when I was 18 so I have no one to ask about him - all I remember is my Dad was born in Poona 1945 so I know Cyril was in India then and I believe his father was in the Army also as a Captain Frank Clarke born 10 Aug 1971 so they all lived in India for quite some time. Thank you so much