Could be the bumper?
I wouldn't discount poor assembly. My bonnet was askew from new, with about 10mm gap on the drivers side below the windscreen and only 5mm on the other side. The dealer said they'd had a 'few' like that. It also wouldn't open correctly. After pulling the lever it was necessary prise the front edge up to get ones fingers in to release the catch. You might also want to check the two plastic adjusters under the lid; screw them in or out by small increments to see if they make a difference.
No Mercky, they're on the underside of the bonnet itself, two hexagonal plastic things that screw in and out. Scraping noises on steep drives are usually the rubber skirt behind the bumper, I've done that often.
I got my bonnet re-aligned under warranty, can you not do so?