In practical terms, the trip works like this:
1. Have a normal day. Have dinner. Pack your stuff.
2. When everyone goes to bed, you head to the station and board your night train.
3. Sleep on the train, and get a small breakfast.
4. Grab a crossaint and coffee in Paris. (optional, but c'mon. You want this.)
5. Board the Eurostar. Get some work done.
6. Arrive in central London in time for a late lunch.