This is an update as I've found I'm still having problems..
I've been battling this recurring puddle in the drivers footwell for quite a while now. It got to the point where the puddle has not only soaked into the foam under the carpet but when lifting the carpet and foam, the puddle was at least an inch deep sitting on the metal
Anyway I tried everything to soak up the water. Wooden blocks, kitchen rolls, towels (swapping every day) and nothing really seemed to work terribly well. I could keep the water under control but the foam under the carpet was still posing a problem
As luck would have it, the missus decided to try some different cat litter for our feline friend. She came home with a bag of wooden pellet cat litter from ASDA:
We noticed that not only does it stop things smelling, it also soaks up fluid like nothing else on earth. Not only does it break up (the pellets are condensed saw dust) it also absorbs liquids VERY well.
Anyway I stuffed some of that under the carpet into yet another puddle and spread it all out under the carpet. Next day the result was staggering - Not only did the carpet have a mountain of swollen wooden cat litter pellets under it, the foam had also completely dried itself right out in large patches. Getting the stuff out was interesting as you can only really do it thoroughly with a hoover which fills up in around 4 seconds - lots of on/off/empty action (don't worry although the stuff is slightly damp it's not really wet). I've since put in a second dose and the water seems to be holding back. The foam under the carpet is now BONE DRY too in the middle. There are still a couple of spots that are damp where the water is leaking in but this is now under control and being absorbed.
So if you're having a problem with a spill or puddle, ASDAs £2.50 wooden cat litter pellets are the way to go!