Kensington High Street

And....one MORE reference from Anna's opening monologue--Kensington is one of the more posh areas of London.

Here's a Wikipedia (gotta love Wikipedia) article about the history of the street:

http://en.wikipedia.org/wiki/Kensington_High_Street

This bus tour clip, although contemporary, does give you a sense of some of the architecture of the area (just, you know, picture it without the few modern buildings and all the logos):

http://www.youtube.com/watch?v=ik48qrLetlY