Greg, there is a Joughin researcher who can probably help you - I'll let him know about your query. He has numerous Joughin families and descendants sorted out, including some in New Zealand.
However you need to give more information about your particular family. Name and date of birth for the Joughin who emigrated to NZ, date he arrived in NZ? Wife's name and dates? Was he married before or after leaving the IoM, etc. The more details you can supply the easier it will be to locate which family he came from.
Sue