Hi fluffymorson Middleton.
A reciprocal agreement between countries means that any tax years in each country may be considered when you apply for state benefits, they are not transferable.
The form CA93A was a guidance booklet for deciding to pay voluntary contributions but circumstances can dictate the way forward.
The process to pay voluntary contributions for non-UK years is different, that was covered in a small paragraph within that booklet. The booklet information is now located on gov.uk -
Voluntary National Insurance Gaps in your National Insurance record
The process to pay for tax years when you are not living in the UK requires HMRC to asses you via a CF83 application to pay voluntary contributions from abroad -
Social Security abroad: NI38
Please read the booklet NI38 on the link, then you will need to decide based on your criteria which class rate of National insurance you wish to apply for. Once assessed we will write back to you inviting you to pay tax years and the amounts.
I would also recommend contacting the New Zealand government regarding your potential pension within that state to see if you are eligible for that countries state pension equivalent.
Before you apply to pay voluntary, first please contact the Department for Work and Pension International Pension centre, they will advise you regarding your state pension and any reciprocal agreement with New Zealand being included. If the years are not included, then they will also advise you if these years would increase your UK state pension if paid voluntarily as some old tax years do not boost a pension as more recent years.
State Pension claims and enquiries from people living outside the UK.
Number - +44 (0) 191 218 7777
Fax - +44 191 218 7021
International Pension Centre
The Pension Service
11 Mail Handling Service A
Open - 8.00am to 6.00pm Monday to Friday, closed bank holidays and weekends