Update on my previous post......
Having located my great-grandaunt in the 1901 census, it appears that Sgt Johnson may have died in Gibralter around 1899 while serving with Regiment. Interpreting the birth places of his children, he was also stationed in Ireland (c.1890 - 1895), Preston, Lancs. (1896), Aldershot, Hants. (1897) and Gibraltar 1899. His widowed wife Jean, is back living in Farnborough with her 5 children in 1901.