If you've got the carpet up Ross you might want to try this.
Get the sound deadening out.
Replace with *dry* newspaper.
Repeat test. This has the benefit of showing exactly where the water is getting to the foot well which may, or may no, help pinpoint the leak. If not, then it's gonna have to be a dash out job, I suspect although does anyone know if removal of the dash top panel exposes the bottom edge of the screen from the inside?
That's a simple removal and could confirm / deny the screen sealing issue.
C