rmgold on Family Tree Circles

Willam Jamieson and Elizabeth (Waddell)Jamieson arived from Glasgow on the barque Jane Gifford arriving in Auckland in 1842, with Elizabeth's brother John Waddell and his wife Catherine (Strain).
William and Elizabeth had 10 children,most born at Union Street,and most of whom I have found entries:
(Agnes died on ship),William b1843; William b1849,James b1851,John b1853, Agnes b1856, Robert b1858,Sam b1860, Watson b1861, Janet b1862.
Robert's burial inscription advises he was the 6th son on William & Elizabeth but I can only find 4 sons born before Robert in 1858. Probably another 1 or 2 two born between 1843 and 1849 but I cannot locate them. Can anybody in Auckland, New Zealand please help ?
Robyn Gold/nee Helps/nee Jamieson