I'm in the middle of doing this - got drivers side done, but rained off on getting the passenger side sorted, boo!
wet vacs good, (I wonder if the fuel stations vac is made for water though!!??) and I'm finishing off the drying with the dehumidifier in the car sitting in the boot. Its been in for 3 days and pulled nearly 3l of water out, going to keep it in til it stops pulling water out I suppose
I have the exact same problem with my drivers side rear footwell, pretty certain it's coming from the driver's side door. Might try and have a look this weekend if it's dry but I'll probably end up having to take it to the garage
what sealant are you using mate, might get it ordered today and have a crack at it on my day off through the week