Give them a call and ask them, some dealers appear to be more on the ball on informing customers of updates than others.
It's a bit hit or miss if you get one who is quiet enough/has enough staff to warrant keeping tabs on every order and emailing every customer an update.
If they are not playing ball with info, then call Audi CS and I'm sure they'll give you an update.
Cheers, sent an email on Thursday to the dealer politely asking when I could expect a build date but not had a reply, think I'll leave it today and if I get nothing then I'll give him a bell tomorrow. They seemed to be very good at keeping in touch before the order and payment was made, I guess they've got what they wanted.