Here is the phone number for Audi Customer Services UK: 0800 699888.
I spent 20 minutes on the Audi UK website yesterday, trying to find it. They would only reveal it to me after I registered my personal details with them. So I did so, got the number, then immediately un-registered.
It really shouldn't be that difficult to obtain a so-called Customer Services phone number, so I publish it here in the hope that someone searching for it might come across this item via Google, etc.