Cheapest I have found and seems they have 10 years history in Melbourne.
Edit: Thanks Maz78 - Apparently http://www.ebay.com.au/itm/Home-security-system-fully-instal… only $520.
Edit: nd here http://www.ebay.com.au/itm/Bosch-Alarm-FULLY-INSTALLED-490-/… $490.
Looks like there are cheaper deals if you look around.
This seems pretty cheap with installation, I do wonder how much is actually hard wired.