The parking sensors have always been over-sensitive, sounding when a long way from an obstacle, but now send out a continuous bleep as soon as I select reverse. I have tried using WD40 without success. Any other suggestions would be very much appreciated.
I would suggest just soap and water next time. Polycarbonate and clear polystyrene plastic are among the few surfaces on which to avoid using a petroleum-based product like WD-40.
It slowly disintegrates most plastics and plastic washers. The damage will not be immediate like solvent on acrylic plastics.
Very many thanks for the advice and I will certainlly bear it in mind should the problem reoccur. However, I suspect on this occasion it was caused by ingress of water into the sensor, as opposed to a build-up of dirt, so introducing more water wouldn't have helped the situation.