We took the sunset tour with London Bicycle company and it was exactly what we were looking for - 10 ish miles overview of the city, able to see much of the city without having to walk or take a bus and personalized discussion and sights based on our interest. We really understood the city much better after the ride and knew where we might want to visit on a future trip as well as how to get around better for the current trip. I also enjoyed that the traffic and crowds (as recommended) were better at night - traffic is a bit crazy and seemed a bit calmer later in the evening.