If you have O2 Travel it will be £6 per day. Travel Inclusive is free You can check what bolt ons you have in MyO2
There are problems cropping up in Australia at the moment due to new Government Rules.
See https://community.o2.co.uk/t5/Discussions-Feedback/Roaming-in-Australia/m-p/1765855#M136179
Best locking your phone to Vodafone Australia
This is not O2 and we are all customers here similar to yourself and cannot answer account type queries.
