Just an update that might help people in the future. The drivers drain hose had come out of the rubber tube/grommet that directs the water out of the car. The hose has a 45deg slash cut but on mine the shorter bit was facing down and it was just poking out of the rubber causing a leak, if the pipe was 10mm longer it wouldn't be a problem. You can access it by pulling the dash side panel off and reaching up under the dash. I managed to pull it down a little to get it back in the grommet. A very useful tool to check things was an endoscope that fits my phone 👍👍. I've cut the soundproof out under the carpet to dry out as it was sodden and have my dehumidifier running in the car. No idea how long it's been leaking but had a slightly musty smell for a while.