He is on the 1861, born in 1855. I can’t find his birth on GRO under Oakley/Skarratt/Skerrett:
Neither can I there's also this record of his baptism
Henry William Oakley son of William Henry and Maria his wife, of Parish of Enfield born
8 Feb 1855 baptised 11th March 1855
Denomination: Disssenters
England & Wales, Non-Conformist and Non-Parochial Registers, 1567-1970William Henry Oakley & Maria Skerratt both single, both resident Baker Street
married
13 May 1854 St Andrew Enfield,
his father Joseph hers John
EDIT to add marriage entry - sorry jamjar noticed you had also posted

Henry William Oakley
1877 New ZealandSpouse Anne Richabina Mullerd
Registration number 1877/951
Henry William Oakley occ Butcher
Electoral year 1881 New Zealand
Residence Adelaide Road
Electorate South Wellingtonedited possibly a different HWO
Henry William Oakley occ TinsmithElectoral year
1893Residence Tasman St Nelson
Annie Rachabina Oakley
Electoral year 1896
Residence Tasman Street Nelson