Ant -
Early start - drive to Dover avec bicyclette, then ride on the ferry.
Whizz down to Boulogne (about an hour)
Pleasant ride through rolling French countryside.
Stop for lunch.
Back to Boulogne (maybe a few beers
) and a bite to eat, then to Dover and drive home.
The car park can be pre-booked (£5 all day last year) or you can take a chance on the local streets (about 5 minute ride).
Paul - I can give you a lift if you want.
Alan, may not be enough for an A and a B group, but it's not an eyeballs out sort of day.