I think the majority of people who are either British or have been her longer than a week do, I mean when you walk to work in the city (like in the square mile) pretty much it's one way on each side of the pavement, or there is a line of people of the left going one way and another on the right going the other, there isn't any bumping into each other. And they walk with some urgency instead of sooo slowly!
Oxford street or Regent's is another matter. Like someone else had said the majority of people poodling around aimlessly are tourists (who amongst other things, don't take into account we drive on the right) but they also dont walk in a straight line because like you say they're window shopping or whatever! Outside Tower Hill station is also another one. People just come outside and stop and them complain when they're bumped into because they're standing in the door way! And dont even get me started on escalators. I mean how many signs are there that say STAND ON THE RIGHT and then you still get a dim wit standing on the left holding everyone up! ARRR. Deep breath!
Ok rant over. Places like Canary Whalf, Lakeside, Westfields, even Bluewater have all the same shops as central london yet none of the annoying people.