Thanks whiteout7.
The death information came from a public family tree on Ancestry. I contacted the person who posted the info who advised that they had been given the info and were not actively researching the family.
I have been following up some tenuous leads as I have drawn so many blanks. The following is what I know about Ellen Walker:
Ellen (Helen) Spencely dau of William Spencely (Sawyer) and Ellen Kendrick born 1823 Grimsby, Lincolnshire. Ellen married William Walker on 24 July, 1842 at Hull.
I have earlier census info, however the 1871 census records William Walker, Saw Sharpner, Ellen, Dressmaker and their two youngest children Samuel born 1860, Bradford and Henry born 1862 in Bradford. The family was living in Biligrave street, St Mary Bishophill Junior, Yorkshire.
William, Ellen, Samuel and Henry Walker migrated to New Zealand c 1878. Their eldest son John Atkinson Walker, his wife and child migrated to NZ arriving in August 1870. JA Walker was sent out to NZ as Manager of the Te Kopuru sawmill in the Kaipara.
William Walker died in Devonport, Auckland, New Zealand on 29 July 1894. His death cert has no info about a wife and children. I have not been able to find any further info on Ellen, Samuel or Henry (mainly because these names are so common) except for a marriage for Henry in Auckland, NZ in 1887. Henry's wife died a few months later in 1888.
I have checked the 1881 census again and found a Bertha Walker, Dressmaker in Alverthorpe. I will check this info again and see if she appears in the 1891 census.
William's father was Samuel Walker, Mariner who died before 1842. I have found nothing further on him either.
Thanks for your suggestions.