In 1718 Humphrey Colquhoun 5th Baronet (age 67) died. James Grant 6th Baronet (age 38) succeeded 6th Baronet Colquhoun of Colquhoun aka Baronet Grant of Colquhoun and changed his surname to Colquhoun.

On 16 Jan 1747 James Grant 6th Baronet (age 67) died. His son Ludovic Grant 7th Baronet (age 40) succeeded 7th Baronet Grant of Colquhoun.

On 18 Mar 1773 Ludovic Grant 7th Baronet (age 66) died. His son James Grant 5th Earl Seafield (age 34) succeeded 8th Baronet Grant of Colquhoun.