Just to go back to the original request.
With that combination of medals he must have served in the 2nd Bn the RSF, which was the only one to serve in the Italian campaign as part of the 17th Infantry brigade (5th Division), after returning from the far East in 1943.
I would hazard a guess that the officer in question joined on the return from the Far East and had been based in the UK prior to that - hence the Defence Medal.
The Bn took part in Operation Husky (the invasion of Sicily) and also took part in the first assault on Monte Cassino.
HTH
EG