Paint can crack and split under intense heat, especially if moisture has got under the surface of the paint if the paintwork is slightly split, once it gets under and you have a lot of heat drawing out the moisture it can cause paint to crack and split, lifting the paint from the surface. Its just what it looks like from the pics, is the paint lifting all the way along the scratch, or just one end?
A bonnet respray will probably cost in the region of £300. A member on here (Coldel) has just had his rear bumper sprayed black and the match is perfect.
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