Just thought I would start up a thread for people to add usefull tips and tricks which are little known ( though invariably in the manual), and less known features. If its any good may be useful as a sticky.
1. For dual zone climactic Air-con, pressing and holding the auto button will synchronise the driver and passenger side with the drivers control (can be undone by simply changing the passenger side control).
2. Pressing and holding the door un-lock button on the remote control key fob will open all the windows (this is not a 'one touch' operation), pressing and holding the door 'lock' button has the opposite effect. (this is especially useful when you come back to your car that has been parked in the sun all afternoon!).
3. Pressing the wipers for single wipe quickly after switching off the ignition will put them in a 'park' position, which is easier to clean, change blades etc
4. One not in the manual, on the newer A3's with the Concert 3's (the double dine one), press and hold the menu button, and the display will go through the 'menu' menu, back, and then a 'test screen' which includes the signal strength for the given station!