My electric window is mis-behaving. It's supposed to drop 5mm when door is open but sometimes goes up and down 5mm continuously while door open. When closing window while door is closed it hits the top and then comes back down 10cm. I suspect it's just a position sensor but Peugeot dealer said it needs a new regulator for £200+vat plus £200 labour for fitting - Outrageous! Any one know where I can get a cheaper solution?