Andy...
You can get the switch (part # 4A0 905 849 B) from an Audi dealer but they will charge you +/-$130.00 for it - that's what they quoted me, you may have better luck in Sydney.
I bought mine (+ a spare) from a local supplier in Qld, the switch is made by bbr automotive, Germany.
If you have the time, getting a couple of switches via the internet from the US (Pelican Parts) or the UK (
www.design911.cm) is the cheapest option.