William Riby Smith is described in the Will of Elizabeth Blenkin as 'the son of my deceased sister'. In his DN his parents are given as Robert and Margaret Smith. This suggests that Mrs Margaret Smith was Margaret Blenkin.
Marriage record of Robert Smith and Margaret Blenkin
Date 24 Jan 1866 Place Pietermaritzburg, Natal, South Africa
"South Africa, Natal Province, Civil Marriages, 1845-1955," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KDCK-JZH : 10 March 2018), Robert Smith and Margaret Blenkin, 24 Jan 1866; citing Pietermaritzburg, Natal, South Africa; 00280; National Archives and Records Service of South Africa, Pretoria; 1,259,160.
Added on 7 Jun 2019 by Ian McArthur