Source: Per post of headstone of this soldier by Greg Melanson from the 18th Battalion Facebook Group.
Family Search: Private David George Flanagan was born on 27 November 1870, in Bethnal Green, London, England, United Kingdom as the son of Thomas Flanagan and Mary Flanagan. He married Emily Louisa Elliott on 2 December 1896, in York, Ontario, Canada. They were the parents of at least 3 sons and 2 daughters. He immigrated to Canada in 1910 and lived in Ontario, Canada in 1911. He registered for military service in 1916. In 1916, at the age of 46, his occupation is listed as concrete construction. He died on 15 July 1953, in Toronto, York, Ontario, Canada, at the age of 82, and was buried in York Cemetery, Toronto, Ontario, Canada.
This soldier, reg. no. 739666, joined the 114th OS Battalion at Hagersville, Ontario on March 2, 1916. He went overseas to England and was assigned to the 18th Battalion on September 9, 1917, joining the unit in the field on October 19, 1917. He served with the Battalion until wounded April 2, 1918, suffering a GSW to the left thigh.
History of the 18th Battalion CEF, "The Fighting Eighteenth" 