[steamship]

Originally Posted by carl81

So I’ve just stuck some strimmer wire up the scuttle drains by accessing through the wheel arch. Plenty of water gushed out!

Sounds promising for this being the likely culprit. You should also clear out the central drainage point, which is directly under the climate unit. This is the one with the copper pipe treatment. The final job will then be to eliminate the entry point into the car itself, which has the affectionate name of 'Botangs hole'. It's best to search for it, so you can view several photos of where exactly it is, and also what others have used to seal it.