When roaming in Australia, your phone will be able to connect to a number of different Australian networks to ensure that you have a strong connection.
I'm not sure if you're aware of this, but, I feel it is necessary to advise you of our stable links policy:-
EE plans are intended for customers with a stable link to the UK who travel abroad periodically. They are not intended for customers roaming on a permanent or semi-permanent basis. We will consider you have a stable link to the UK if spend a total of 60 days or more during any 120 day period within the UK. If your usage abroad in the EU/EEA exceeds this, you will be alerted by text, and after a 2-week period we may charge you for services you use or block your SIM card and roaming services. We’ll let you know before we do anything.