Someone asked about this a few days ago and I thought they were referring to the current model, not one two generations ago. Your problem is almost inevitably due to blocked bulkhead vent well drains.

The vent well is the area under the grille at the bottom of the windscreen. It has a drain either side that is prone to getting blocked with leaf debris. Your problem could also be the pollen filter that sits in the vent well. If the seal has failed or if the waterproof top is cracked or displaced, rainwater will drip or even flow into the car. Same with same generation Golfs, Leons and A3s.