Hi, Recently having my A4 Cab. serviced at a local Audi specialist, they carried out a diagnostic on the front and rear parking sensors. It showed a faulty rear inner sensor. They quoted me £202 to supply a genuine Audi sensor, paint it and replace it. Having spent a lot of money recently buying the car etc, I would like to attempt this myself, could anyone give me any pointers, does the sensor replacement require the rear bumper to come off, if so how does it come off? or can I simply gain access to the sensor from underneath, any help or advise on this will be greatly appreciated.