Its hard enough to restore the finish on headlamps( I had to work long and hard on my Clio II to do so) but on a much less accessible and relatively large surface area of a ForFour roof it will be quite a project I fear. If that aerosol of clearcoat is for two headlamps, and only lasts a year according to the blurb , will there be enough for the roof panel, and how long will it last on as horizontal suface?
I was at a classic car show recently, and asked both the polish outlets and the two valeting firms present about rectifying and maintaining the roof, and none had a convincing solution.