Yay! I think I have cracked it. A big bit anyhow.
Parents Adam Knowles and Maria (nee Dale) Knowles of Manchester, England are listed as having the following children christened: Jane (1820), Sarah (1823), Joseph Dale (1827, the right date for "ours", first boy so middle name is mother's maiden name..just as "our" family legend says), Harriet (1829), Frances (a girl, 1831), Helen (1833), and William (1836). The parents were married 29 Dec 1818.
It all lines up, so I this this is he. That is Joseph Dale Knowles who married Elizabeth White in new Zealand.
I haven't sighted any of the actual documents, which is a pity, so I have no parents' details. I found the info at the Family Search site at https://beta.familysearch.org/search/records/index#count=20&...
He may still be the Joseph mollipops tracked down for me travelling to australia and new zealand.