Mums fiesta flooded (sounds like driving a bath!)

[Tiggsy]

so my mother was moaning her rear seat floor mats (drivers side) where wet - I looked and they were SOAKED. I then drove it and each time you brake there is a sound that seems like LITRES of water is sloshing around under the car!!!!!

so first of all - can i just drill a hole thorough the floor to let the water out (and silicone it up after)? And the hunt down the leak?

They are looking at £££££ to ford otherwise (they spent £450 on the EXACT issue 18 months ago they said!)

Car is 10 years old so no warranty issues about drilling holes in it!