I have a problem with my 520d touring which is stuck on its lowest suspension setting. I have had it checked out at BMW who are telling me that the well under the boot floor is full of water and the sensors are consequently full of water. Apparently there are 4 of them and they are telling me it'll be £500 per sensor. I was wondering if anyone can tell me if they are available cheaper than that and if they are likely to be a problem to change - or is it necessary to get them set up electronically using some fancy gizmo that I don't have.