Ford Focus - warranty vs wear and tear

My car is due out of warranty next month. I have just been advised by Green Flag (starting problem) that the fan belt and tensioners are worn, and should be changed. The car has done 35,000 miles. Is this acceptable normal wear and tear or is there a case for replacement under warranty?
Fan belt, auxiliary belt, fine. Not expensive. A 1.8-litre petrol is a chain cam Mazda engine so this is not an expensive timing belt.
Answered by Honest John on

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