Problem now sorted!
It was the drainage plug under the battery (blocked with gunk!)
Took the battery out, then cleaned out the plug. Had to lift the carpet behind the drivers seat, tough job! but all done now!
A hell of a lot of water was removed from rear well (over 3L) Even though it didn't seem too bad, once the carpet was lifted it uncovered a very thick underlay. This is where all the water was.
If you need any pointers, please feel free to ask.
Good luck!
Tony Henry
November 2008