We found a local newspaper article (Islington Gazette - Tuesday 16 June 1903) reporting on the marriage, the previous Saturday, of Florence Minnie, daughter of Joseph Toomer, of Falkland Road, Harringay, and Frederick Walter, fourth son of W. H. Callow, of the North London Carriage Furnishing Warehouses and the Islington Van Works, and also of "Willard", Highbury Hill, N. "Miss Toomer, who is a sister of Mr Walter Toomer, the well-known tenor, has herself a fine soprano voice and is very popular." She had attended the Quadrant Church for 19 years and the wedding drew a crowd.
Assuming the 19 years of church attendance began as a baby, this gives her birth year as c.1884, and she would have been aged c.70 when the church was rebuilt in 1954.
The reference to Willard was puzzling. We found that "Willard House, Highbury Hill, London" was an address in 1905, but we can find no other reference.