This can easily be done in a Custom Event. Create a new Championship, 1 Event, 2 Stages.
Select any Stage you're comfortable with driving (I went with the shortest route in Spain).
Select it twice and make sure there's a Service Area in between.
Set the AI difficulty to 1 (Very Easy).
Damage your car on the first stage, even bodywork damage will do (damage it near the end of the stage to be safe).
In the Service Area, repair the car.
Once you've won the Event and continued on past the podium it should unlock.