Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first
What income will you have to live on when you move back to the UK?
How will you maintain yourself - what will you live off?
Any income you have from any source is available to pay child maintenance
If you stop payments then your ex can obtain a Court Order in New Zealand that will be enforceable in the UK.
I asked what you will be living off to gain an idea of how much you may have to pay