My girlfriends A4 cab had a repair in 2004. The rear drivers side wing was badly damaged and so was the door. The guy who repaired it cut out the section of damage in the rear wing and fixed in a new piece from the new wing. He said this was done to keep all the original wing (and therefore the seams/lines) so that the car still had the original fit around the roof, rear lights and bumper. Now nearly two years on rust is appearing around the wheel-arch and the paint is oxidising. I am taking it back to him on Thursday but not sure what to do. Do i trust him to sort it out for no doubt free, or take it elsewhere? Not sure what they could have done to cause this. Any advice guys??