Rear wiper fault

Hello everyone, I'm new to this forum. My four year old Skoda Octavia Elegance Estate is by far the best car I have ever owned, I bought it new in May 2009. However the one irritating fault, which Skoda don't seem to be to fix, is the rear wiper which has had a life of it's own for the last twelve months. In warm dry weather it sets off when not switched on - I can stop it temporarily by doing an extended wash-wipe but then later it starts again. Skoda have replaced the motor and the control box which regulates the car electronics, and for a time all seemed well. But now the warm weather has arrived its happening again. In cold or wet conditions the problem doesn't arise. If they can't fix it when it goes for a service shortly I think I'll ask them to disable the rear wiper until next winter!! I know Octavias have had rear wiper problems reported, but I've not seen this issue discussed - any ideas?? Thanks