Yes, I'd remembered she was very young.

Hmm ... just having a think about how best to help with this.
The peculiar thing about these marriages between young girls and older men, is very often the man "still told fibs" about his correct age. !! (He may have been even older than 33).
Will have a look at the microfiche index in the next day or so and see if there's a James HENDERSON birth reg'd. at Dunedin.
* I'm guessing you don't have birth printouts for any of his children, which might help clarify his birthyear ?
Lu