Thanks for your efforts. According to the 1911 census William (50yrs) and Ann (47yrs) are living in Haggs/Bonnybridge with Elizabeth Kelly aged 15 who is working as an envelope maker in an Explosives Works. She is referred to as adopted, and her place of birth is recorded as Lanark, followed by what could be ?Partic. There's writing over the top of it unfortunately. The couple have 2 young children living with them, William (4yrs) and Margaret Ann (1yr), who i have found are the illegitimate children of their daughter Margaret Ann. She married Henry Thomson in January 1911, and she is living with him by the time of the census, leaving her illegitimate children with her parents.
The census also states Ann had 2 children, 1 living- this is Margaret Ann.
Just to clarify, i was getting names mixed up- when i originally posted Ann Kelly, it was in fact Elizabeth.