While it might be that hve you checked the water isn't simply coming out of the heater box drain pipes. If you look at the heater box there are 2 vents, one each side. They basically spill water onto the car mats.
It's an idea John but I think the water is running down the outer edges of the footwells and the heater drains are on the inside of the footwells near the gearbox tunnel. However it's a thought and I will check again.
