It is hard to guess what age Andrew Skilling was when he was with Sarah.
His occupation showed as ploughman when his daughters' Agnes and Sarah were born in 1925 & 1926?
There is an Andrew Skilling, ploughman, working for a Francis Wilson, farmer, at Guiltreehill Farm in Kirkmichael, Ayrshire on the 1925 VRs.
1935 VRs show an Andrew Skilling, ploughman, working for a John Y Currie, farmer, at Southook Farm in Dreghorn, Ayrshire.
The name of Andrew Skilling is not common on the records. So, to have records showing an Andrew Skillling and the occupation of ploughman makes you think they may connect to the Andrew you are searching for.
Monica