Hi there
Try this: Prise out the central air vents. BE VERY CAREFUL. The front flaps and ring may come off first but stop pulling on them. You want the complete unit – a tube about 6 inches long.
I have only removed mine last weekend to fit a new radio in. The driver side came off quite easily in one piece. The passenger side however was a lot harder. In the end the flaps came dislodged from the main tube, which was not the end of the world since this allowed me to remove the tube bit.
Perseverance paid off I must say..attached is the image from Doblo eLearn..