This is an image of the farmhouse at Corehead taken by Chris Halliday. It is no longer owned by a Johnstone.
There were 2 Johnstone families who owned Corehead.
The first Johnstone of Corehead family was descended from Herbert, 7th son of Sir Adam Johnstoun.
The second Johnstone of Corehead family was descended from an illegitimate son of another branch of the chief's family.