Drifting back towards northern France over the next couple of weeks aiming to return via one of the three Normandy ports..Cherbourg, Caen or Le Harve. We haven't booked the ferry yet and asking if there are any "tricks of the trade" or so to speak such as booking the night before..is that cheaper?...turn up seeking a cancellation and which of the three is usually the cheapest anyway? I certainly don't want the horrors of Calais or the M25 . Thank you in anticipation.