I'd agree with cdeavionics. They look like the hangars 5 and 6 (later renamed TBF) at LHR they would have been opposite what is now TBK.
There were Skyways aircraft used by BOAC as I can vaguely remember some of the engineers who were subcontracted to look after them.
They had 'railway lines' laid into the hangar and the a/c were pulled in sideways. (parts of the tracks can still be seen!).
In fact upto the late 70's there were still a couple of Merlins stored in one of extensions on the side of the hangar on the left.
