Hello, I am hoping to get some advice on what to check for a leak in the drivers footwell on my MK5 Golf. It's a 3 door with no sunroof. Every time it rains I get water build up in the drivers footwell. So for I have tried clearing out the drain holes underneath the wipers and inside of the wheel arches so that water can drain properly (these were clogged) and re-sealed the bonnet release grommet as it looked a bit worn. I've checked the windscreen and can't see any obvious leaks and I do not get any signs of the windows steaming up etc.
I did have a local garage check the leak but by their own admission they didn't really know what to look for. They stripped down the bottom half of the dash and left a hose on the car overnight. They said the water was leaking in through the brake servo but that to replace the seal on this they would need to remove the engine so I left it. While I don't doubt that water is leaking in through this I can't see how it's even getting down that far without draining or where it would build up to leak through the servo.
Any help would be greatly appreciated.