Hy Les
I had the same problem, i spent about 12-18 months trying to find how the water was getting in, i found that the only way to do that was to take the carpet out, Then i think you will find all of the drivers side at least will be flooded.
When you have taken the carpet out dry the inside of the car, Then you can pour water on the front wind shield to see where the water is getting in, DONT be tempted to seal the place where the water is coming in the car on the inside, Seal the out side where the water is getting in, you will find how to remove the carpet on here,or go to you tube.
My car is Rover 75 CDTI Club
David
Have a look on here might help
http://www.the75andztclub.co.uk/foru...emoving+carpet