I took the ferry to Sweden and back again, and I think that flying to a place for a "green" vacation is a contradiction in terms. Obviously crossing the Atlantic or Pacific requires a flight, but to really be kind to the planet, travelling surface is the way to go. If you have to fly, you should make sure that you are staying for a long time. Hopping on a plane for a week holiday is about as ungreen as it gets.
You can take the ferry in Newcastle and come back via Harwich for a nice round trip;
Send your feedback or queries to email@example.com