A metal rod had almost gone through the bumper (yellow circle).
I removed both rear lamps, license plate and the rear bumper.
The bumper is fixed with 8 hex socket (Allen) screws. 2 screws behind the license plate. 2 screws underneath the bumper and 2 screws on each side in the wheel arch.
To remove the bumper from the plastic "locks", push it downwards at the same time as you lift it away from the body.
I used an old iron on the inside of the bumper in order to push the bump back out again and to flatten the plastic.
Then I used some plastic filler and 600 grit sandpaper to make it "smooth" on the outside.
I took the whole bumper to a paintshop and had it resprayed. The color code for the Corsa you will find on the B-pillar on the right hand side. In this case it was Y474 (yellow circle) Casablanca white.
Y474 is equal to 10L and 10U.
The final result was nothing less than perfect.
