Hey, noticed this topic and another about the ferries to Le Mans. We always used to get the Portsmouth Le Harve / Caen Ferry but the last 3 years we have tried using Norfolk Line which sails regularly between Dover and Dunkerque. Maybe worth having a look for next year. We paid for 2 adults and a car which came to just over £30 return (it was about £50 in 2007). It one of the longest ways of travelling but nice and cheap
I used Norfolk Lines for the first time to go to Spa and paid £28, for 2 plus car, service was good too. Only problem for me is that the extra distance from Dunkerque is fairly costly in fuel at 13mpg, so there isn't much cost saving (if any) for going to LM. I'm on P&O this year, £68 for Car + 2 wasn't too bad.