The passenger mirror glass has been wobbling since we bought the car and then yesterday it fell off. It looks like the previous owner was a bit ham fisted when they replaced the glass and broke the disc that the glass is supposed to fix to. As a result it's only secured by three out of four of the lugs that it locks on to. It looks like the mounting plate is simply screwed onto the front of the positioning motor. Is it possible to replace just the plate or can I only get the whole assembly?