I have found birth records for twin girls born May 5, 1817, baptized June 6,1817, named Amelia and Matilda. Parents are Joseph Davie and Ann Sutherland. They are living in a poorhouse in Greenwich, Woolwich, England but not as inmates. It shows Joseph as a Corporal with the Sappers and Miners, which also is on his findagrave. As for Emily I will keep looking. And I don't know if Joseph and Ann were married. More research required.