Bill Elkins ex Old Oak Common (June 1964/November 1984). says "Looks very much like Ealing Broadway (Down Main) to me. I stand to be corrected though." He's correct - Google Earth found those flats in the background.

Can anyone say what 6150 off Slough was doing on the Down Main displaying A headlamps. Must have been a really tightly diagrammed service, perhaps Paddington, Slough, Reading (Oxford). Normally the preserve of a Hall, but with no reporting number displayed perhaps we will never know