Happy to have a chat with them next time I'm in there...I've been using them for almost 10 years for various different Audis, new and old!
I think they're mainly used for their collection / delivery service... They'll come to your house in a an A2, leave it on your drive while they take yours back to be serviced, then swap round when done. I guess it makes more sense to leave a few grands worth of A2 outside someone's house than a shiny new A1!! Plus, they're more likely to get noticed! I don't think they're actually used as customer courtesy cars.