Heads up for those doing an online renewal.
There is an issue with the online forms. It won't let you save the information you have filled in, or pay the fee, unless you input A mobile number for a GP.
However GPs don't give out mobile numbers in general.
To get the data saved I put my own number in instead, and then contacted Te Tare Pureke today, to find out that its a known issue with the online forms that has not been fixed, and that what I have done is an acceptable bypass.
There is a section at the end where you can leave a note evidently, informing them of what you have done.