Help with Paternal Grand Fathers Siblings and Parents Montgomery

Looking for my paternal grandfathers family
William Montgomery. Born 1905. Died 1972 in loanhead Midlothian Scotland. Married to Mary Richardson Stewart (tennant ) adopted by the tenants they married in -1932 I think.
I am Looking for Williams parents. I think his father was Andrew. And mother Christina. And I believe William had 9 siblings.