Where is park distance control unit located?

Will someone with good hearing please listen carefully where the warning sound for the park distance control eminates from, and then let me know?

My 2005 TD4 HSE has got the factory fitted rear park distance control. The "buzzer" became hoarse and had now gone completely quiet. I have been spoilt by this and want to bring it to life again. I have been looking for this unit in vain. Always thought that the sound came from somewhere towards the rear of the vehicle, but a strip of the load compartment only revealed the ECU and two units for the rear window and rear window wipe.
I fear that the buzzer and other electronics re. the park control may all be part of one sealed unit. The electronics were/are still OK, and it is only the "buzzer" that is giving trouble.
Please help me to find this unit so that I can a) try to take if apart; failing that b) order the right part number.
Thank you.

The control unit and the buzzer are behind the rear left panel in the load area

Bleeper should be affixed here. N/S behind light cluster.

Yup, that's where mine was when I fitted the trailer wiring.
Deepends where they decided to bolt it on, position may vary but it is there.#

Thank you for the advice. It did help a lot. Eventually located the "speaker" (as the dealer calls it) near the top on the rear RH shock. Replaced with part from dealer and it is now working 100%. BUT: I believe that any tweeter at a fraction of the cost of an OE part would do.

Thanks again.