Hi SazMcG:
Abbey Road Studios has an excellent web cam pointed at the Abbey Road street crossing where the photograph of the famous album cover was taken. Check out the action to see if you might want to visit this site which, according to a guide book (not RS) is about twenty minutes by subway from central London.
http://www.abbeyroad.com/crossing
It is fun to watch the action of the tourists who want to mimic the album cover as they interact with vehicular traffic.
I will be in London in late summer and might check out the action here.
Geor(ge)