A Telecom SIM I have here starts with 530051 (53005 being XT's MCC/MNC code) but is the full 15 digits.
Also, why is the "My number" field not set on the SIMs? All the NZ Telco's seem not to do this so they have to be manually set via a phone that supports writing this field, which most phones don't do. It's not often anything needs it, but a couple of phones I've had have made use of it for self-ID purposes.
