Am i really going to make that much of a difference if i take the family on holiday to devon as opposed to flying out to sunnier climes in the Med? If it rains on a uk holiday, I'll be using the car far more than usual, whereas on a foreign holiday....once there, the only footprint i leave is one in the sand.Hmmm.

Yes it will make a difference. Flying pushes out an amazingly high amount of carbon, and I don't think you could get near it in a car, even if you drove a Hummer around non stop for 2 weeks!

Assuming you have a more normal car, and spend at least some time on the beach, then you certainly are helping.