In the early '70s, when I was instructing at Manby, we used to do a 2 day round UK low level trip for those returning to fast jet flying which involved stopping overnight at Macrihanish. On one of these trips my Wg Cdr "student" and I left our accomodation to go to the Mess hut and the Wg Cdr, looking back to our accomodation, saw that the word "SHELTER" was written on the side of the building.
"Tell me Caz" he said "is that the Building's secondary function - or the name of the Organisation that own's it?"