Hi Malcolm,
There would normally be no problem getting it to germinate. Grow in average garden conditions (cool root run, reasonable drainage, not too exposed, average sun and moisture). Easy from ripe seed (before the rats and birds have reached it). Information taken from Gardening with New Zealand Plants, Shrubs & Trees by Fisher, Satchell & Watkins (publ. Collins). At home years ago, plants would self seed and come up in the ground or may have been bird dispersed. Moist topsoil, reasonable light. No problems... Keep trying!