I am looking in the 1891, 1901 and 1911 censuses for Mary Hollist Heppell, who married William Masson Wilson in Chelsea in 1880. She was born in Islington in 1851, parents Lionel Charles Heppell and Mary Ann Baxter or Heppell, and she may be the one who died in Brentford in 1916. Her husband was born in Bothwell, Lanarkshire in 1859 and died in Edinburgh in 1884. They may be the parents of Louise/a Masson Wilson, born 1883 in Pancras and died 1899 in Westminster.
In 1881 she is listed as Marry Wilson, aged 25, born Islington, living with her husband in Willesden.
In 1911, there is a Mary Wilson, widow, 61, in Chelsea Hospital, birthplace given as Westminster.
Not being familiar with where Westminster ends and Islington begins, is it possible that the one in Chelsea Hospital is the one I am looking for?