Just thought I'd update this for completeness. Last week we reported a funny noise with the car (after having it for 7 days), and they booked it in to the Audi garage. We have picked it up today, and they've fitted a new clutch, flywheel and bearing under warranty. They would have done it sooner but has to wait a few days for parts. We also pointed out that a USB charging point in the arm rest did not work, which they forgot to do, but Cinch have also approved them to do the work so we've got to take it back on Monday and they will fix it whilst we wait.
So, a £1500 (at least) job done under warranty with no quibbles, we're pleased so far with the service.