I'm moving back to O2 from EE and am currently in that no man's land of waiting for it to port over. Turning the phone off and again to see if my number had magically appeared in the address book (instead of the temporary O2 one). But I wondered what the actual process was and where the number is stored. Is it on the SIM, phone or with the network provider? (or all three?) Anyone know how it all works?