Perhaps another way of travelling with Eurostar. You can start booking now and the trains start in May with a daily train in the summer months.
Journeys from the heart of London or Ashford to the centre of Lyon, will take about four-and-a-half hours, while Provence will be reached in a less than six hours, or Marseille in just over 6 hours.
London to Marseille would be approx. 111 euros return.
Check out the Eurostar website and there is more info in the Connexion.
http://www.eurostar.com/fr-fr
