Should an Audi A3 need a new gearbox after 48,500 miles / 3.5 years?

I have an 08 plate Audi A3, owned from new, which has done 48,500 miles. The differential has broken, requiring a new gearbox. Audi UK have washed their hands of it and the dealer are reluctant to pay the bill as I am not intending to buy another vehicle from them (I wonder why?). I have argued the sale of goods - duarability argument, but am at an impasse. Do you think this is a legitimate position for Audi to take, leaving me with a £1,300 bill?
No, and I am more than a little surprised because this is not the sort of position Audi would normally take. So there must be some reason for this.
Answered by Honest John on

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