You can't have another NZ Working Holiday Visa. It was granted, and that is your one grant - the fact that you never used it makes no difference.
If you’re outside of New Zealand and we’ve approved an earlier application for you to have a New Zealand Working Holiday Visa, you can’t apply for this visa. This applies even if you didn’t use that visa.
However, if you are 35 or under, you may like to look into using a BUNAC IEP visa. See here.
https://www.bunac.org/uk/work-abroad...inclusions/iep
We’ll check our records for any previous New Zealand Working Holiday Visa approvals you may have had.
Previous approvals, here.
https://www.immigration.govt.nz/new-...-visa#criteria