Getting an NT tax code to avoid paying tax twice

I have been trying since last August to get an NT code because I live and pay tax in New Zealand. I withdraw an annual pension sum and transfer it from UK to NZ; it is being taxed in the UK too, and - on advice from HMRC - I sent form R43 by post to get a refund and change tax code. I have had no reply after sending two copies of the form R43 and a further letter, but I see my tax code has now been changed to 1257L rather than NT. Why would this be? I cannot telephone as it would cost a fortune from NZ, having to wait up to 50minutes.

Hi,

A form R43 will not give you an NT tax code as this only gives you personal allowances. to be fully exempt, it is a DT individual form that you need.

Double Taxation: Treaty Relief (Form DT-Individual)

Thank you.

Thank you, I have sent the DT-Individual form and got the tax code changed. On the same form I requested a refund but I have not received that. Do you know why? Is there anything else I can do?