Registration for Self Assessment - Overseas

Hi, I am living in New Zealand and have income in the UK that I need to declare in a self assessment. I have applied to register for self assessment, but the application keeps getting rejected saying the the address on the application form does not make the records that HMRC have. I have checked and they are identical save that the information for my profile has no postcode (there is no option to insert one) and the application asks (and insists on) a postcode. The address (on both my records and the form) is in New Zealand, which is where I live. The application form says that you can register with an overseas address, but it just keeps getting rejected. As mentioned above, the only difference between the addresses is a postcode. There is no option to include a postcode on my records through the HMRC app, presumably because it is an overseas address. Do I have to apply using the physical form instead? If so, come on HMRC, pull yourself into the 21st century. Thanks.

Hi Christopher Powell,
We are sorry you are having issues registering for Self Assessment.
If you are unable to register online you can download and submit the SA1 form to update your records:
Register for Self Assessment if you are not self-employed
If your address needs to be amended but unable to do this online you can contact HMRC to update here:
Self Assessment: general enquiries
Thank you.