Correct Krystal n chips, on the Domestic Site (Now DLO Caversfield) the old Bk Blks were converted into wards, the 'New' Junior Ranks (New, in that it was built in 1939 ish along with the 'H' type Bk Blks) was turned into theatres and ICU's.
The old Offrs Mess which became the Sgts Mess was left untouched and in a right state (Refurbed when DLO moved in), the new Offrs Mess up the road may well have been used as well, but I'm not sure on that, its now a care home.
Over the road on the Tech Site a lot of the Bldgs were used by the Americans, notably one of the 'C' Type Hangers which was refurbished and used as part of the US Complex, possibly as the Med Stores, and the old armoury/education Bldg was also used. In fact, judging by the exterior paint jobs and internal decs (lot of brown paint used lol) most of the Tech Site was used. The American Boy Scouts even used the Old Station HQ Bldg.
Around 1939 the original Med Centre on the Domestic Site was extended to include a Decontamination Area and Ward which was basically two hardened Bldgs partially covered with earth banks and lots of concrete, the Casualty Decontamination Bldg being attached via a covered passage to the Med Centre while the other Decontamination Bldg was a stand alone.