I've just spoken to my Service rep at my dealer and initially she said, 'Yes, it needs a fluid change'. When I queried this, she checked her 'system' and realised that my car didn't need the fluid change - yet.
Apparently, there are 2 makes of quattro, Haldex and Torsen and if one has the Haldex, then the fluid change is a lot more often. It appears that the A5 has the other type and she quoted me fluid changes at 20k & 40k miles.
She went on to explain that (as mentioned elsewhere), the dealer (or Audi UK?) marketing people check the database for owner's with a quattro of the right age or mileage and just send out the cards to all and sundry.
My wallet has breathed a sigh of relief - having just paid out for a service on my MX-5 yesterday.