I have had the same noise from when I got the car. It has been getting louder recently.
I did an' inlet valve clean up' this morning -(post on this to follow) - and then an Italian tune up to clear the system. Couple of red lines and some revs up the A3. I normally drive pretty gently.
One of the first things I noticed when I got back, less noise from that area ...... Can't really explain it other than my brief session of spirited driving 'freed' something up?