Should the brake discs on my Nissan Qashqai have corroded at just 11,500 miles?

I have a two-year old Nissan Qashqai, 11,500 miles, which was serviced today at a Nissan dealer. The garage say that the front discs need replacing as they are scored and will rust and that this is not covered by the warranty. They quoted a price of a little under £400. Is it reasonable to have to replace the discs after such a short time, and at my expense, as one might have expected a longer life than this?

Asked on 23 November 2013 by SM, Leominster

Answered by Honest John
This is an unusually short life for discs but may have occurred if the car has been left standing outside in winter for extended periods when the perpetual corrosion to brake discs can be much worse due to road salt. The first drive of the day usually scrubs off overnight surface corrosion, but if the car is left unused for days or weeks the corrosion eats into the discs.
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