I had something similar. This was on the top of the tailgate, alongside the high-level brake light, see pic. I got my local equivalent of "Chips Away" to look at it, he pointed out that there was quite a large area of repaired paintwork around it. I've had the car from new, and to my knowledge there's been no repair work in that area, so it looks like it was done before delivery. My guess is that, realistically, some panels will get damaged in the factory so they must have some repair scheme for that. In this case it hasn't lasted as long as it should. I suppose I could have got the dealer involved under the 10 year paint warranty, but in this case it'd be his word against mine about whether I'd had a bodged repair done and frankly life's too short. Couple of hundred quid to my local man fixed it.