My model ends in BTU but it does have "R-NZ" on the back of the box.... (photo below)
It does make sense that R stands for Region....but that could just be a co-incidence.
Anyhow, ordered a new one for delivery tomorrow. Will see if that is any different...
I have not activated it, but the official communication went internally to EE CS earlier today. I would say try over the phone and let them know that the information is available in their internal system called Albert. The plan costs £7 / month with unlimited calls and texts and 10GB data. First 3 months are free.
My onenumber is active if call the number goes to answer phone, but if I go to onenumber and try to login it just times out and saying something when wrong, send a text to it and it sends but goes nowhere, oh and I do not get a text saying I have a missed call, it has apparently all been reset yesterday and they would call me back at 15.00 but no call.