There is no reason in principal why Santander cannot take account of a New Zealand power of attorney and release the requested information to the attorney. You might want to get an English lawyer to examine the Power of Attorney and express a written opinion as to whether the POA complies with the requirements of English law. The chances are that it might, given that the laws of England and New Zealand aren't too far a part when it comes to executing documents. If that doesn't work then you will have to go to the Court of Protection for a court order and that will require the services of a solicitor as the application may not be straightforward. It can be tedious enough even without the international dimension. I hope that helps. Please leave a positive rating so that I am credited for my time.
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