It's not that hard to travel to London. Well, if you plan your trip nicely, you can see the whole of the history in less than 5 days that would include clubbing and little trips outside the cosmopolitan as well. Lonely planet is indeed a great guide for the world traveller but I would rather opt for the suggestion from those who are living in London - friends to be precise. I don't know much about France though but it's not far from london if you take a ferry ride from down south Dover. btw, take waterproof clothes, August is the season!