Water in footwell

[thowman]

The passenger footwell of my car fills with water when the car is left outside and it rains. Therefore it is a problem with a seal somewhere. overnight, the car filled with about 2cm of water in the footwell, and no signs of drips anywhere - so I assume it coming through the carpet after running down the bulkhead.

Also just noticed that where the headlining meets the passanger windscreen pillar, the headlining is damp. So, I guess the windscreen is leaking? Is it not bonded in place?

Any ideas where I should look for the leak without having to take out the entire dash?