I'm new here so hello everyone. Picked up my 65 plate S3 on Saturday and love it. Parked it in a car park for only the second time today and came back to find a black line about three inches long on the drivers door. To say I'm gutted is an understatement. Gave it a rub but it's not budging. Not sure what it is but it's on the surface and not a scratch. I've never detailed a car in my life. Can anyone recommend me a product to try to remove it. Cheers.