As we are willing to take mid week bookings - and be flexible with dates - this may enable you to obtain a good ferry deal?

From UK the drive from Calais/Boulogne to Cap de la Carrere is 9 hours on the road using the main/toll roads. Allow 11 with stops. Allow 11/12 hours on return and you should be OK with stops/Paris/check in times.

The drive from Santander if you take the Plymouth ferry from UK is 4 hours.

The cheapest ferry from UK is Speedlink from Dover to Boulogne - this is a fast and cheap crossing allowing you to pick up the motorway system south.
This page may be out of date as we tend to use the Chunnel and are not at all up to date with the latest ferry deals.