Yeah, I had a 147 with the same problem.
I'd bring it to a dealer who has experience with fixing rattles though.
My dealer who had zero experience with this sort of thing, as it was the first 147 which came back for rattles, made it a whole lot worse. So much so, the dash and instrument panel sounded like a bag of marbles. And the centre airvent started acting up.
Kendr, thanks for the advice on fixing the centre console noise on my the 156. My dealer removed it, all the screws, greased everything up, and now no more buzzing. Also, they added some kind of foam underneath to absorb and "new noises". It's going back on Friday though. As they never fixed the continuos tapping which is coming from near the gearbox. I think it might be a loose cable from the radio or heater, down the side of the centre console. I also noted, that if you tap the side of the centre console (near your left leg), the CD player skips !!! Any ideas ?