Renault Scenic - Scratc repair - helmet

Been to look at a Scenic 1.9 DCi today, and the car is not bad for a Renault, however, I noticed a long scratch on the passenger rear door about 15-18 inches long which doesn't to have appeared to be too deep, but the place that is selling the car has tried to touch it up with a paint pen.

The car is the right price for the money, but I'm thinking to make it just that little bit nicer, I would like to get the scratch eliminated elsewhere.

What sort of price might we be looking at to do it?