Bren your memory fails you!
It was used when the VCR was refurbished in the 70's/80's.
During a night shift (ah, got it you didn't do many of them
) the Tower Controllers worked from the caravan whilst the chippies made new desks in the VCR.
It
was some time ago, as one of the Merchantmen (Vanguard freighter) was doing an engine warm up close to it, came on the R/T with "morning campers".