June Uni Meet Question (UK and France)

Hi Everybody
I will be in the UK and France during June on a business trip. I won’t have a unicycle with me. The coker itself probably exceeds some luggage regulation, and unless some miracle happens between then and now I’ll still be an embarassingly pathetic rider.

My itinerary is as follows:
Thursday 17 - Arrive London, day at London office, travel to Wells in the evening
Friday 18 - Day at Wells office (Meetings ALL DAY - GOODY!), travel to London in the evening
Saturday 19 and Sunday 20 - London. My time is my own but I MUST be at Waterloo in time to catch the 3pm Eurostar as I need to be in Fontainebleau by the evening
Monday 21 to Friday 24 - Fontainebleau
Saturday 25 - Day in Paris, flying home on the evening flight

SO - is there anything on that I absolutely cannot miss? Are there any shops I MUST see? Is anybody likely to be in that general vicinity so I can pop by and say hello?

TIA for any info or suggestions