Sometimes depending on how the car is parked, water finds its way into the car and runs down the windscreen and all over the dash. So far this has knackered the radio/satnav. Someone suggested that this may be due to blocked drainage channels. Any ideas how to fix it, or also any other potential causes. Also deos anyone have the Harman Becker radio/satnav spare for a 2002 Series 2 TD5.