Sadly, I caught a bit of "Does Doug Know?" on Channel 4 this evening. Even more sadly, I recognised where the "member of the public" participation was filmed - I literally walk along that bit of road every day on the way to work. It was by the American Church on Tottenham Court Road, diagonally opposite Heal & Son.
When I worked on Millbank, it was less of a surprise to see it on TV (given the proximity to Parliament). But Tottenham Court Road? A minute's walk from the Scientology shop?
Hmmm. Maybe that explains a lot...