Wet Carpet on 53 plate ulysse

After doing a spot of shopping at my local Asda, I got back into my 2.0JTD Eleganza (Ex-Addison Lee) to find it wouldn't start. There was then a loud beeping noise coming from inside the car and the front headlamps came on (and wouldn't go off) Nothing worked electrically. I tried to locate the Battery as the Handbook stated that it is in a Scuttle in front of the Passenger Seat. I eventually found it (in front of the Drivers Seat), and disconnected the battery. When I connected it again the car was ok, and has been since. Whilst looking for the Battery on the Passenger side, I found that all behind the carpet was soaking wet? Has anyone else encountered this or does anyone have any ideas as to where the water can be ingressing?

That will be the air con drain.......Had exactly the same on my 53 Peug 807, (the worst car ever !)

Pull off the cover on the side of the center console at the floor, (where the foot air vent is). You will see a rubber pipe heading towards the floor. Its connected at the base or the Aircon unit then goes to the floor where there is another joint. Mine was blocked and leaking at the top joint. I pulledthe pipe out, poked a stiff plastic pipe, (washer pipe), down thro the floor to clear it, then reassembled using a decent jubilee clip in place of the tiewrap thing that was there originally.

I left the carpet to dry, took weeks !

Cheers
Gerry