Location of rear parking aid warning buzzer and help - A4 cabriolet

[endlessheadroom]

My PDC has been playing up recently so took it to have the fault codes read.
All the sensors are doing the "click when you listen to them" trick but the full scan of the system has shown up a code as follows:

1543 - Rear parking aid warning buzzer H15
Open circuit/short circuit to earth

As my reverse buzzer had been sounding a little ropey recently this makes sense.
The question is - where is it located and is it easy to get at to remove?

Also, any thoughts on what might be causing this with the buzzer - could it just be a loose connection?

Thank you

 

[Cyrix]

It's under the boot carpet trim on the passenger side, on the Avant anyway.

 

[Craig Cull]

As above, same on all

 

[endlessheadroom]

thank you

The only issue I am facing now is how to get the carpet trim out of the way to get under it - how is it all held in place?