Walshie, here's another thread -- water entering via the side mirror, running down the wire harness through the bottom of the door and into the footwell.
http://986forum.com/forums/general-discussions/22781-drivers-side-footwell-wet.html?highlight=Wet+door+panel
You would only have water building up in the a/c drain if the a/c was running. I don't think this is the problem.
Good luck my friend!