There is a bewildering variety of routes and means of transport for getting to France. We have tried most of them. St Julien is about 500 miles from Calais/Dunkerque and about 350 from Caen. Driving times are around 8 hours from Calais via Paris using the péage (toll motorway), 7 hours from Caen. I can supply suggested routes that seem to work, including how to get round Paris avoiding the dreaded Boulevard Périphérique and a route from Calais via Rouen which takes under 9 hours (the route we normally use).
There is intense competition, particularly on Dover/Calais and prices seem exceptionally low. Eurotunnel (0990 35 35 35), SpeedFerries, Norfolk Line (0870 870 1020), P&O (0990 980 980) and Sea France (0990 711 711) are all based in Dover or Folkestone and cross to Dunkerque, Calais, or Boulogne. Further west you can cross from Newhaven, Portsmouth, Weymouth, Poole and Plymouth to ports such as Dieppe, Le Havre, Caen, Cherbourg, St Malo and Roscoff. Try Transmanche Ferries, Brittany Ferries, Condor Ferries or LD Lines.
You can also fly with Ryanair or Flybe from Stansted, Newcastle, Liverpool, Southampton, Bristol, East Midlands, Bristol, and Exeter to Poitiers, Limoges or Bergerac (all about 1.5 to 2 hours from the house) or Angoulême (less than an hour). Or take the train to Angoulême in about 6 hours from London. There is a bus from Angoulême to Brantôme that meets an evening train from Paris 4 days a week. Car hire is easy at airports and Angoulême station.