Well I have a solution..Seriously..don't laugh.
It's worked for me.
Use a hose on the windscreen to find out EXACTLY where the water filters through. With the bonnet open feel around the padding under the scuttle to see and investigate better.
NOW ! Here's the strange bit. !
Get a cheap metal plate, the type used for barbeques, cheap at supermarkets. Fold it in half and tape it to the underside of the leak. You may need to cut/shape it slightly but as its really bendy you can use your fingers to shape it as required.
When it gets hot, being metal inside the engine bay, small leaks will evaporate, larger leaks would hopefully flow away from the dis pack...depends how well you shape and position it. Its not difficult.
You are basically forming a channel from the shaped surface of the plate to send water off, away from vital bits. So far...working well for me.
Ok ! You can laugh now.