No problem - they agreed to fit a new part under warranty no bother. I also had a paint defect in my wheel arch which I had spotted when I was washing the car at the start of the week (the car's first wash)and this is getting sorted too - new arch to be painted and fitted next week. Here's hoping there's not a third thing!
It was a bit weird though at the dealers - the car was clean and they still put a hose over it.