Hello - thanx for the further posting.
Margaret Duff was my Grandfather's aunt, and I get the impression they were very close. There are a number of pictures of them together in the family album. Margaret's sons were John and Robert, and they farmed at Ravenswood, a poultry farm near Cumbernauld. The group photo at the front door of Ravenswood ( in a previous posting) shows Margaret, and John Anderson. Both died in 1942 within days of each other - TB.
I recall meeting either John or Robert when I was a child, in the late '50s. I do not have any further information regarding the Duffs. All the data I have posted comes from personal memories, and family anecdotes handed down. The Anderson names you mention seem fairly common, and can be seen in previous postings. best wishes.