Can anyone confirm this as a drying room please?

I am not sure that is, the boiler room was brick built, against the smallest Nissen hut on the crew rest & drying room complex. I would suggest that it is a communal site building.

One of the buildings at HMS Inverailort was described as something like that. Can't find my picture but was a brick building and looked as if there was a water boiler / heater. They trained there in amphibious operations as well as on the hills (which would be just as wet!).

I suppose to much to expect the military to refer to existing buildings but most Highland estates had a drying room where wet clothes could be left a day out shooting on the hills.

The US Navy SEALs had a great one in their building at Machrihanish. There is a large area that vehicles can drive into, it has cages where each person can leave their equipment to dry. I think there was a communal shower to wash off sea water (probably before removing dry / wet / immersion suit) then proper male and female showers each complete with a Jacuzzi.

I wondered because many of the officers would come from a background where they would be familiar with the drying rooms on sporting estates.

I have seen this one, it is in the laundry building but the same principle applies.

canmore.org.uk/collection/684328