It may be that the previous owner had the function switched off
You could ask the dealer to reinstall the function via the scan tool but this would cost
Chances are it has LED lighting, if not then I would fit a bulb with a reverse beeper built in
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2499334.m570.l1313&_nkw=reverse+light+bulb+with+beeper&_sacat=131090