The dealers can "swap" cars between dealer groups but they tend to stick with in there own dealership groups probably due to the accounts side of things.
If there is a Audi which is built and to your spec in the country somewhere unregistered, then it would of been ordered by a dealer to be put on as a demo. As far as I know if a dealer orders a car for this reason, then they can't sell it for 3 months or until the car has done 3,000 miles.
Brands like Ford, Vauxhall etc have cars parked up, built but then they aren't "built to order" like Audi's, BMW, Merc etc...