George
As to whether it is William and Sarah the only link I currently have is that John William Callow was living at 9 Murray's Road in 1900 when he got married, and his father was one William Callow. In the 1901 census as we know JWC was on board ship and his wife lstaying at her parents but there is William, Sarah and other Callows living at 9 Murray's Road. I'm reluctant to accept that as firm evidence that the Murray's Road William and Sarah are his parents, I feel I need some other confirmation at least!