Wow, I definitely didn't think about the channels through the chassis. I'm gonna investigate mine hopefully this week to see. Great job and thank you so much for that insight.
I had the same problem with my first gen skoda Fabia,,The seals would fail on the rear doors and let water in ,,,They all suffered with this problem,,,,A fantastic way to get the carpets 90 percent dry in just 5 mins,,,,Here in Ireland we have co op stores that supply farmers with everything and anything they need,,,I'm sure England has something the same,,,Just get the largest cow syringe you can find ,,,,without the needle part,,,push it down into the carpet and suck,,,,,You won't believe the amount of water you can extract from a carpet,,I'm sure you can also get these syringes on line,,
Won't really do it.... water gets trapped underneath the carpet (which is plastic) and insulation (closed cell plastic foam). No other choice but to pull the interior unfortunately... THEN use an industrial dehumidifier.
Best way to get that carpets to dry is through a ground sheet or seat covers on the floor do the same on the top and drive over it foam traps water and it doesn't like releasing it even with a breeze. Guess ya body shop bay doesn't have an oven
On vw it'll be the mastic on the rear doors ,,you must take the door cards off and you'll see a plastic type material with silicon or mastic type stuff sealing it,,,This fails,,Just get a silicon gun and some TEC 7 and seal it ,,,,