My leon had the same
problem.
Water was dripping down around the pedals, turns out it was a seam in the vertical bulkhead (not where the loom enters) that was not sealed properly.
The seam is just below the bottom of the windscreen at the very right.
I had to strip down the fusebox and lower part of the dash to trace where the water was getting in. If you strip the right side part of the dash/fusebox area you can see better.
Thanks,
Neil.