In the newsagent today were lots of advertisements for this promotion. You can claim up to 5 free bottles but no more than one per day per mobile.
Text YES, space then your date of birth in the format DDMMYY to 67444. You'll then be sent a text back with a code on it - show this code at the counter and you can claim your free bottle. The code will expire within 12 hours of it being sent. It says standard network charges apply and doesn't say there's a charge for receiving a text back from them (although it states PAYG users should have sufficent credit to both send and receive messages)
Closing date 28 June