Sir John Sinclair of Longformacus, 4th Bt. (died 1764) (d. 1764) Parents Sir Robert Sinclair of Longformacus, 3rd Bt. Christian Cockburn Children Sydney Sinclair Siblings Christian Sinclair unknown daughter Sinclair unknown daughter Sinclair Sir Henry Sinclair of Longformacus, 5th Bt. Jean Sinclair Partners Sidney Johnston