So this spring our extension pitched roof had to be replaced entirely. (It's an old house and we're working our way through the jobs that needed to be done when we bought it, which was why it was cheap, but we've got there.)
As a result of the leaking extension roof, there was a chunk of plasterboard above the back door which had rotted through. So basically, currently, a hole in the plasterboard over the door.
The thing is, the last couple of times it's rained really hard, we've had about 30 drips of water come through that hole. I've been out and looked at the roof, the roofer is coming back tomorrow to check that it's all still good, there is no damage or slippage and it only happens when it's absolutely hammering down, and then only briefly.
Is it possible that it's condensation from the body of the house gathering on the roof battens through this gap in the plasterboard and then dripping off? The builder won't replace the plasterboard till it's all dried out underneath, but if that's not the problem we don't want to have it all to do again in six months anyway!