Thank you Frances, and yes it is a stressful time giving information at the time of Death.

(thanks to Sue, who found this Will in the index at the Auckland Archives)

Date of Death 26th September 1910.
Will dated 2nd August 1910.

Wife of John Corkhill of Wyndham in Otago.
Children, Walter Henry Corkhill and Mona Corkhill, Executor and Executrix.

This is the Last Will and Testament of me, Sarah Jane Corkhill of, Gisborne, late of Otautau, Southland.
Estate included : a dwelling house and half-acre of land, situated in, North Otautau, Southland.

On the 6th page of the Will :

In the Supreme Court of New Zealand Gisborne District.
I Walter Henry Corkhill of Gisborne, Carpenter make oath: and say as follows:-

1. My Mother the said Sarah Jane Corkhill did for many years prior to her decease live separately and apart from her husband John Corkhill.

2. SOMETIME ago I saw a Deed of Separation between the parties, though the same is not in my possession.

From the: Historical BMD New Zealand,

Marriage,
1864/2843Sarah Jane Powell

Births,
1866/1644 Corkill Ann
1867/2369 Corkhill Ada Jane
1868/1984 Corkill Thomas
1869/172 Corkhill Frederick William Sarah Jane John
1871/2603 Corkhill John Robert
1872/2992 Corkhill Ernest
1874 Corkhill Walter Henry
1876/14169 Corkhill Sophia Annie Sarah Jane John
1876 Corkhill Louisa J.
1879/12089 Corkhill Allan Vannon Sarah Jane John
1881/8935 Corkhill Francis Worthington Sarah Jane John
1885/2809 Corkhill Maria Armstrong Sarah Jane John
1888/4674 Corkhill Mona Sarah Jane John

John Corkill in Waimate a Stonemason on Sophia Annie CORKHILL Birth Certificate 14 October 1876.
John Corkill in Waimate a Farm Contractor on Francis Worthington CORKHILL Birth Certificate 30 June 1881.

and under: Contractors and Carpenters: J. CORKHILL in Otautau Business Directory in 1905 in Southland.

Cemetery Search Results - Otautau
ht tp://southlanddc.govt.nz/cemetery-search/

CORKHILL, Sarah Jane
Maiden Name POWELL
Date of Death 01 Jan 1910
Age 64
Cemetery Otautau (New)
Location of Grave Block A II
Plot 28
Grave Markings Headstone on concrete base

CORKHILL, John
Occupation Stonemason
Address Invercargill
Undertaker J H Pay
Date of Death 18 Feb 1916
Age 79
Cemetery Otautau (New)
Location of Grave Block A II
Plot 28
Grave Markings Headstone on concrete base

CORKHILL, Walter Henry
Date of Death 01 Jan 1943
Age 69
Cemetery Otautau (New)
Location of Grave Block A II
Plot 28
Grave Markings Headstone on concrete base

CORKHILL, John Robert
Address Otautau
Undertaker W R Ireland
Date of Death 08 Nov 1946
Age 75
Cemetery Otautau (New)
Location of Grave Block A XII
Plot 37
Grave Markings Concrete ground

CORKHILL, Louisa J
Maiden Name FINLAYSON
Address Otautau
Undertaker W R Ireland
Date of Death 10 Jan 1951
Age 75
Cemetery Otautau (New)
Location of Grave Block A XII
Plot 37
Grave Markings Concrete ground

CORKHILL, Francis George
Undertaker J F
Date of Death 20 Jan 1967
Age 56
Cemetery Otautau (New)
Location of Grave Block A XIII
Plot 2
Grave Markings Headstone on concrete base

CORKHILL, Francis Worthington
Address Invercargill
Undertaker J F
Date of Death 26 Apr 1969
Age 88
Cemetery Otautau (New)
Location of Grave Block A XIII
Plot 2
Grave Markings Headstone on concrete base

CORKHILL, Annie Maria
Maiden Name PHILPOT
Address Otautau
Date of Death 05 Dec 1957
Age 69
Cemetery Otautau (New)
Location of Grave Block A XIII
Plot 2
Grave Markings Headstone on concrete base

CORKHILL, Allen Vannon
Date of Death 21 Dec 1904
Age 25
Cemetery Otautau (Old)
Location of Grave Old Cemetery Block VII
Plot 11
Grave Markings Concrete wall, earth ground

I have also found entries in the New Zealand Electoral Rolls that place the Corkhill family in Otautau and Gisborne in various years. (from : Ancestry)