I'm not related to the Bushe family or Mary's family but I did a bit of research.
There was a Mary Marr born in 1897 in Doncaster, Yorkshire. I'm not sure if it's the same person? On the 1911 census, Mary is 13 years old and living with her mother, Eliza, in South Kirkby, Yorkshire. She had two brothers, Laurence and William, and a sister, Annie Elizabeth. Again, the surname is Marr. Her father isn't recorded on the 1911 census but there is an Eliza Marr living in Durham in the 1891 census with her husband, Edward Marr, and more of Mary's siblings, Helen/Ellen, Bridget and Patrick.
There was also a Mrs Mary Bushe (nče O'Marr) in the Women's Army Auxilary Corps. during the war.
Hope this is the same person!
Anna