finally got to the bottom of this- my migration was incorrect and the reason being is that a good proportion of his clients have actually been onshore when their visa had been granted, according to him the department of immigration has acknowledged the clerical errors with this and have ironed out the 'kinks within the system' to avoid thus happening in the future.
So looks like I will have to go to NZ after all. Will make the best of it though as I have never been before. First family holiday abroad :-)