These are distinct from the lands of Ballumbie, which were last in the possession of Robert Williamson of Ballumbie, hence there is a Laird of Ballumbie Castle as well as a Laird of Ballumbie.
Ballumbie lands are distinct from these; they were once under the control of Robert Williamson of Ballumbie. Consequently, there exists both a Laird of Ballumbie Castle and a Laird of Ballumbie.