West Channel crossings are preferred because it’s a very long drive from Calais / Eurotunnel (559m / 8h 10m)

Brittany Ferries operate crossings to Le Havre, Caen, Cherbourg and St Malo (nearest)
From: Caen (Ouistreham) To: Saint-Martin-de-Gurson
Driving Distance: 405 miles Time: 6 hours, 54 minutes

From: Le Havre Ferry Terminal To: Saint-Martin-de-Gurson
Driving Distance: 431 miles Time: 7 hours, 30 minutes

From: Cherbourg/Gare Maritime To: Saint-Martin-de-Gurson
Driving Distance: 447 miles Time: 8 hours, 3 minutes

From: Saint-Malo/Terminal Ferry du Naye To: Saint-Martin-de-Gurson
Driving Distance: 358.1 miles Time: 6 hours, 19 minutes

I travelled from Cherbourg this weekend because my ferry from St Malo was diverted. It was 474 miles according to the sat nav and it was a very long drive (9 hours with two 5 minute breaks). Not recommended!