OK, update from my side.
I went to the local SC yesterday for a creaking noise inside the cabin, which they fixed.
When I mentioned the problem of the rattle, with the technician inside the car with me, he said it was caused by some support for the windshield going all the way down to the frame of the car. He mentioned that removing these supports solved the problem, but obviously that's not a good solution as these supports are there for a good reason.
He mentioned that they were still waiting for a definitive fix from the factory.
Anybody else heard a similar story?