With all this rain we've had the Golf has sprung a leak and it's a big one. I emptied out about a litre of water from the footwell yesterday and I've got about the same today

I can't find anything obvious and searches have thrown up all sorts of ideas from the pollen filter (not likely as it's only the rear) to the sunroof (if I had one)
Has anyone had this and what were their solutions? I want to rid the car of the water as it's annoying having to bail out every day plus I can't be doing with the condensation. I've got a fan heater running in there to dry it out now
One thing I am going to try at the weekend is resealing the window mech panel as I had this off in the summer to replace the window runner...