I've only had my XC70 a week, but one night we had very heavy rain. The next morning, I needed to put something in the boot before setting off - but when I opened the tailgate water started dripping through into the boot. Looking inside, it was coming through the internal roof trim (if you look inside the boot and upwards, there is a rectangular piece of roof trim that runs the width of the boot, and has a seam at either side pretty much level with the two edges of the opening hatch - the water was dripping through these seams on both sides).

I know that I locked the car the night before, and I know that the boot wasn't open (I have the electric tailgate, so I always shut it with the button rather than manually).

I opened/closed the tailgate loads of times to check that it was closing properly and it seemed fine. I tried to recreate the problem by pouring lots of water over the top of the car, and into the gap between the car roof and the tailgate, but couldn't recreate the problem. We've also had rain since that night (albeit not quite as heavy) and no problems.

So I guess I'm asking whether anyone else has had this, or has any ideas what might have caused the problem. Given that I can't recreate it, I'm not sure the dealer would be able to either, so any advice would be great.