For example, one of the Retronaut readers found this view of Grosvenor Chapel in Mayfair on Google Street View, and it matches up nicely with the Butterfield photo #4 here. Another reader found a contemporary Google Street View on Sloane Street near Sloane Square, which shows how much has changed architecturally on that street since Butterfield took photo #3 in 1949. Note the men wearing hats.
Photo by Chalmers Butterfield.
http://www.howtobearetronaut.com/2010/01/1940s-london-in-stunning-hi-res-colour/ - via twitter