PapersPast :
William George DURHAM (father of Alfred John) begins appearing in Auckland newspapers from c. 1885. For some years he worked as head bailiff / Sheriff's officer (Auckland Council ?) and later as the manager for the Auckland Merchants and Tradesmen's Account Collecting and Debt Recovery Association. [search on "Wm G. DURHAM" ].
In case you don't have this, William George DURHAM, died 1895 and is buried at O'Neills Point Cemetery, North Shore, Auck. His wife Ellen (recorded as "Hellen" or "Helen") died in 1893 - cemetery record at Purewa Cemetery (Auck.)
There is also a probate file for William George DURHAM at Archives NZ, Auckland.