Thank you, fdm, for your most helpful post.
I was shocked at the level of service Audi provided. Ironically, my A5 caught fire on the way back from an Audi garage after I had just put in an order for a replacement demonstrator. What really amazed me is that following the fire Audi refused either to supply a courtesy car or release the demonstrator to me. This meant I was left without any means of transport whilst trying to sort out the mess.
Needless to say I cancelled the order! In contrast, BMW had a car outside my office within fifteen minutes of me calling - now that's what I call service!
I sent photos of my car on fire to Audi the day after the blaze, but received no reply. I sent another email and again no reply. When the case was eventually picked up Audi seemed totally disinterested even though I and my wife have been loyal customers of the brand for many years. My A5 was bought from an Audi dealership and serviced exclusively by Audi. The fire brigade thought the cause of the blaze was likely to be electrical, but of course as the car was burnt to a shell there was no way to verify this beyond reasonable doubt.