We had an absolutely "smashing" time touring London with the outstanding driver/guide "Stevie!" Told him we'd already been to the castles and churches, so Stevie took us to the open air markets, where we ate oysters the size of your hand, a 200 year old pub where he bought me a pint, The Globe Theatre where Will didith his thing, and the graffitti underground where all that spray painting is legal, gorgeous and mind boggling... and many more places. Stevie was interesting and knowledgeable, a great conversationalist, had stories to tell and IS a story in his own right. A few days after after our tour, he was honored by Parliament for being one of the blokes who stopped the knife wielding assailant on London Bridge! Our tour guide is a hero!
If you think you won't be comfortable in a classic Austin Mini (and I did,) fear not, it is much roomier than you imagine and the tour was, absolutely, a highlight of our short stay in London. Can't recommend it highly enough!