Bugger!
We have roof leaks.
The symptoms are:
Leaking from above window frame in two rooms.
Water running down light in hallway, just behind front door.
Chances are, this is the weatherboarding on the gable, which runs nearly the length of the house.
I have some sealant, but it will be a bugger to apply. The roof pitch is too steep to walk on, and I can't even use roofing ladders to access this bit.