The Eurostar can get you from London to Chambord (change in Paris) in just 4 hours of travelling time. Why not take a break and hire a car to explore the fabulous countryside after or before the meeting? Or take the ferry from Portsmouth to do a little wine tasting and replenish your wine racks, we will after all be visiting Chateau Valmer and their prize winning wines are well known in the Vouvray region. A cheaper and slower way to go is to take the bus from Liverpool Street station in London to Paris and then the train to Blois-Chambord. My Trainline app shows fares from around £30 per leg depending on what time you travel.
Here are some more photographs to whet you appetite.