We did the half day tour of London's main sights with David Simmons as our guide and Robert, the driver. As it was Boxing Day, there were only 5 of us, which was perfect! We hopped on and off for photo ops, toured St. Paul's Cathedral, saw the changing of the Calvary and all the main sights, like Buckingham Palace, houses of Parliament, Trafalgar Square, etc. David was very informative and an incredibly interesting guide. I'd recommend his tours (he works privately too) anytime.