Sadie is the diminutive name of the name Sarah. James and Mary, both born 1895 in Bedlington, had a daughter Sarah Jane, born 1914. They had two other children: William George born 1918 and Phyllis born 1919. I think the child in the photo, if she is known as Sadie, is probably Sarah Jane. Could the photo have anything to do with the end of WW1? Early 1920s?