I just dropped something down the side of the drivers seat (door side) and stuck my hand down to retrieve it. Imagine my suprise when I felt damp. So I pressed firmly against the carpet with my hand and it was soaking!
Checked the passengers door side and under passengers seat and it was dry as a bone. Stuck hand under driver seat and it seems to be just around door area. Then I pulled the drivers side floor mat up and sure enough, the carpet is wet!
Argh, what the hell?
Where's it coming in, how do I stop it and more importantly, does my car have some hidden history that is likely to have been the cause of this?!