If i lived in England, was £20000 in debt to the bank(nat west) would i be able to sell up and move to New Zea?

...land without paying the bank money owed (paying off my mortgage but not the money owed.

Well if you're on the other side of the world it is quite hard to see how they could pursue you for the debt. I'd do it.

No, because the requirements to get a permanent residence visa for New Zealand are among the toughest in the world and your financial status is one of the first things checked.

Don't be so stupid, if this allowed, everyone would do it.

no, your credit is checked