Discovered (boom boom) that the front carpets are drenched underneath - but no signs of it above. No clue how long they've been like that. I've got the carpets out and drying in the lovely sun, so now I need to get to tracing where its all got in from. Could do with help not only where, but more specifics of how to get at/find some of the places; as well as how to test and fix.

It's not red, I'm not losing that sort of quantity of coolant, and it seems to be near the doors, so it's not heater matrix. And I don't have any sunroofs, so not that either. Had the headlining completely replaced just a couple of months ago, and there were no signs of leaks then, nor any wet patches on it now. I did used to get damp patches at the tops of the A pillars, but I stopped those years ago with a little external sealing work to the gutter ends. I've also already looked at the A piller drain holes, and assuming they're supposed to only be a few mm deep at that point, they seem clear too.

Two things I have identified are the holes in the floor (body mount access?) weren't plugged. I've added grommets now - but how much water would realistically make in through them (I don't even off road, let alone wade)? And secondly the seals around the door straps are loose. I guess water would get in there, especially heavy rainfall; but wouldn't that drain out through the A pillars? Any good suggestions what to use to reseal those up?

I've also had the air con drains suggested, but again it seems like a lot of water for that to me. But worth checking, I just don't know where?
Or the drain along the bottom of the windscreen? How do I get in there and see if there's any issues?

Any help with how to trace and fix appreciated.