Should my car need new rear brake discs after just 12,000 miles?

I have a 2015 Volkswagen Golf GTI that has done less than 12,000 miles and which has just had its 2 year service at my Volkswagen main dealer. They have told me that the rear discs and pads need replacing as they are 90% worn. Is this normal wear for a car of this mileage?

Caused by a combination of light use, overnight rusting of the brake pads to the discs and the electromechanical parking brake system dragging when released.

Answered by Honest John on 3 May 2017