I have been given a "Sim-free" iphone 4 in the UK (currently on holiday)
The details with the phone say it will lock to the network it is first used with.
I'm struggling to find information on how it actually works?
Is it a feature or software on the phone? Is it a feature of the uk networks pushing settings to the phone?
What is the best way to make sure it works in NZ?
Do I just leave it in the box till I get back to NZ or am I best to use it and then get the network to unlock it while in the UK?

