Not on a MINI, but on a Rover 75, which has system that behaves exactly the same and I think it is identical.
It wasn't working at all. I found the connections between the control box and the sensors themselves had come loose. The connector was behind the rear bumper and attracted a lot of mud, so it just needed cleaning up and the individual pins inserting back into the connector housing.
We had our first snow this morining and when I got in the Mini and put her in reverse I had this non-stop beeping. Put it in neutral, it went away. Sad to say I had to do this a few more time to figure out snow was covering the PDC.