I'd third Newhaven – Dieppe, I've done it a number of times, bike touring and driving. It's not as popular as others, so is quick to get on, the boats (IMO) are nice, the train is faster than Dover from London (I think 1h 15). The boat tickets are cheap (I think from £28 each way).
You can get a cabin if you're getting an overnight ferry. It takes 6 hours overnight or 4 hours in the day, arriving at 5am in summer time, which is perfect for starting a tour.
I'd third Newhaven – Dieppe, I've done it a number of times, bike touring and driving. It's not as popular as others, so is quick to get on, the boats (IMO) are nice, the train is faster than Dover from London (I think 1h 15). The boat tickets are cheap (I think from £28 each way).
You can get a cabin if you're getting an overnight ferry. It takes 6 hours overnight or 4 hours in the day, arriving at 5am in summer time, which is perfect for starting a tour.