Reversing sensors

Have an annoying issue with my reverse sensors on the oct 2 vrs

2nd time the car has been in the garge and nothing was done today (as the fault didnt happen again)

Issue is that every so often when reversing, the "Beeb" will be sounded. even tho their is nothing behind (anytime while reverse is engaged.. moving or not.. .. gives false readings)

Now this can happen anytime of day or night / any wheather conditions (intermittantly)

I have the problem now that for skoda dealer to do anything they need to have this happen to them, this means a full day of a techys time to sit and play with reverse

(which they will no doubt bill me for time), this may not even happen on the day of testing.. so then their would be a second day involved or even a 3rd

The sensors them selve have had a fresh coat of paint va the same dealer i have been to today, and they are aware of this. but as the car is coming out of warentee tomorrow, I think they are reluctant to swap them out completly.

I have no time for them to have the car/loose more days off.. should i contact skoda direct? any thoughts on this one?