Originally Posted by Passmethesickbag
Your only option is to spend the night in London on your way back I'm afraid - nobody will get you to LHR early enough to catch your connection by train or air.
The first flight of the day is:-
Flight: British Airways flight 303 on a Airbus Jet - non-stop
Depart: Paris de Gaulle, France (CDG) - Sun, 27 Jun at 07:40
Arrive: London Heathrow, UK (LHR) - Sun, 27 Jun at 08:00
So you might ask BA and VS whether 90 minutes is enough for the T4-T3 connection that you would have to make.