We had a short, sharp shower yesterday and whilst the rest of the car remained dry I got some water dripping down from the headlining onto the rear drivers side seat. After it had all dried out and the sun had come back out I got a watering can and dropped some water on the rear quarter of the roof on that side and hey presto dripping headline. Now this "removable" roof is a bit new to me as I've not had a car with such a thing and I am wondering if a bad seal is the cause. I've had a look in the gutter and that looks ok, but there's a small gap between the roof panel and the rubber top of the window rubber and that would be about right for where it's coming in (it drips down the centre of the seat). I was thinking of trying some sealant in the gap and trying the watering can again, but should I use some sort of flexible sealant and would some stuff from a DIY store do?