Cleaning the car today,and noticed a nasty rust bubble starting at the top of the windscreen,just where the roof meets the windscreen rubber.Is this common on these,and has anyone else experienced this.Car is 51 plate,and this must be a bad water trap,because as you peel the rubber back,you can see all the water lying there.Was thinking of running a bead of clear sealer under the rubber,and it should be totally watertight after.