I understand that non-NOK can obtain limited Service Records of deceased personnel, the Government portal is here:
https://www.gov.uk/government/collec...ervice-records
There are a number of genealogy sites specialising in service records, but some may cost. Google is your friend. As you have his number, if you haven't already you can use that to search London Gazette records. A quick look shows he transferred to the RAFVR on 13 Aug 47, and relinquished his commission on 13 Aug 52 - so it was presumably a 5 year appointment. His first appearance in the Gazette in 1943 - commissioning?? - gives his full name as George Samuel Jupp.
I had a quick look at the 1939 Register - a sort of mini-Census to inform ID cards - and it throws up two George S Jupps. As this Register gives dates of birth, we can I think discard the one born in 1882 - a little old to be flying in WW2. Which leaves "our" George S Jupp, dob 30 Oct 20 - whose age seems about right.
In 1939 he was living with Mum and Dad at 47 Harden's Road, Camberwell, London. Dad (also George) and he were both listed as "Transport Contractors", George Jnr being specified as "porter".
There should be something to be going on there - fortunately I was in "Genealogy Mode" when I saw your post - that was about half-an-hour's searching - and no bill will be sent!!