Thanks, Carol, that's much clearer.
The left hand car is an Austin A30, which according to Wikipedia was made between May 1952 and Sep 1956. A registration number beginning SGF would be consistent with that, and would have been issued in London - October 1955 onwards. (Source:
http://www.oldclassiccar.co.uk/registrations/reg-letters.htm)
The other car is a Morris Traveller (the estate version of the Morris Minor). The slatted front grille came in in Oct 1954, and the split front windscreen went out in 1956, so it dates from around 1954-56. The best match I've found in registration letters to fit that date is a series beginning DM (ie DMA, DMB etc - 15 in all), which were issued in London in 1954.
Based on this, I'd tentatively suggest the building might be in the London area.