No it wasn’t under warranty but the audi dealer apparently raised a claim with audi UK and they agreed to reduce it to £500.
FYI, just got a call today that the part will be replaced today and they will perform an extended test drive.
fingers crossed, should get the car this week!
I suggest you call AUDI UK directly and lodge a complaint regarding the part and how it shouldn’t be needing replacement after 4 years etc.