You must take this tour!
What a wonderful way to see the city! Our guide Birgit was so knowledgeable. I learned so much from her about so many London locations, and so many English language idioms! I'd recommend taking this tour near the beginning of your time in London as it will help you get your bearings and decide what to investigate further. We were very lucky to have a very small group - only three of us plus our guide - and Otto at the store was so helpful getting us set up with bikes, helmets and rain ponchos. Couldn't possibly recommend the London Bicycle Tour Company more.