As I stated in my posting, that is all the information I have. I have checked all the information that is available. I think he slid down a rainbow to get to New Zealand, probably Port Chalmers. He must have come steerage, and their names aren't on any of the lists of immigrants. They are usually shown as "55 in steerage".
The only hope I really have is that someone researching another member of the family has a James and William that they can't track down.
If there was a census for the period 1840 to 1865 I would probably wouldn't have this problem. I suspect that his parents were James and Elizabeth but that is only on a certificate that is very suspect.