Re: Moss Bros... If you go to 14:11 here you'll see it here in the 1979 BBC adaptation of Tinker, Tailor, Soldier, Spy: https://www.dailymotion.com/video/x6f0gn7
He enters and goes down into the long sealed-off basement arcade which used to look like this:
https://www.glasgowtimes.co.uk/resources/images/7821855/?type=responsive-gallery-fullscreen