Hi again, I am out of my comfort zone/area when dealing with Scottish ancestry, to help out I can only provide census returns which hopefully will assist!
Are you/we happy that the returns I have already posted are in fact the correct family, if this is the case then a couple of questions need to be verified eg on the 1861 census Thomas is shown as "Son in Law" but in 1871 he is a Widower with Sarah shown as single and acting as a servant for him, is William with the family in 1871 a brother?
Was Thomas a widower when he married Sarah?
Keyboard86