Thank you for all your replies, I`ve a lot to think about!!
As far as I know there were no children from this marriage, but as there are 11 births in the 1920-1927 window, I`m not sure if I am going to go down that route!!
My mother used to say that "auntie" Mary was an only child, with no children, but I have discovered that Mary Scott had 2 half siblings.
The 1901 census may show the rgiht family; on the marriage cert one of the witnesses is a Mary Graham.
Thanks again.