When washing my car the other day I noticed sum rust on the bodywork between the rear right light and bumper it is not that noticable because its between where the plastic bumper meets the upper body panel. can any1 tell me what my best option is to cure this problem is the paint covered by BMW? I have a repair certificate from BMW for some work done before I bought the car, not sure if its for this area though. would that work also be covered? If not what is the best way to stop the rust spreading?