Hi, I have an A3 Saloon Quattro 2.0 S Tronic 190 TFSI with mag ride and 19" wheels. The car has only done around 7000 miles and is just less than a year old. It seems to have developed an odd constant hollow metallic noise in the last few months from the rear audible from 15 mph upwards. It doesn't change pitch. It is not road noise as it is higher pitched and doesn't change with speed. Has anyone else experienced this?