Message received in my bank account inbox on 11 April.
May only be available for St George / Westpac / Bank of Melbourne / etc customers.
Same as the previous deal http://www.ozbargain.com.au/node/70052, but likely with a new registration code.
Direct link - https://partners.bitdefender.com/media/html/au/stgeorge/inde…
For 50% off other BitDefender products - Suggested by xerot in the comments below - Consider using a different currency store - such as US/Worldwide: http://www.bitdefender.com/?ctrsel=1
50%OFFBD2013
NB. It may be kinda broken at the moment due to a an apparent system error on their side.