A bronze tablet in honour of Nursing Sister Mary Agnes McKenzie was unveiled in the Avenue Road Presbyterian Church on June 27, 1920. Nursing Sister McKenzie lost her life on June 27, 1918, when the hospital ship Llandovery Castle was torpedoed. The dedication ceremony was conducted by Reverend Dr. Alfred Hall, Senior Chaplain for Canada to the Institutes of the Naval and Merchant Marine Services. A naval Veteran lowered the naval flag and Mrs. Mill Pellatt unveiled the tablet.
The Presbyterian congregation joined the United Church of Canada in 1925, thus the church became the Avenue Road United Church. In the mid-1970s, the building was sold and the plaque was moved to Calvin Presbyterian Church.