I had a problem with water getting into the passenger side footwell for some time. The scuttle drain below the battery was checked as this can block but that was not the problem.
I eventually used a bottle brush to clean out the drain holes at the bottom of the windscreen near the hinge point of the bonnet. I was not aware that they were there until i shoved the brush down. The car has been dry for years now.
Worth a go, it takes minutes to do, best to have the bonnet open.