The family of Buchanan-Baillie-Hamilton is connected to the Leny family via Buchanan of Bochastel. The first of the Bochastel family being Walter Buchanan third son of Andrew Buchanan second of Leny.
Sir Arthur Buchanan first of Auchlessie, who was the second son of Walter Buchanan seventh of Bochastel, married twice; (1) Jean Drummond by whom he had (1) John who died before 1701, (2) James who succeeded, and a daughter Janet. By his second wife Elizabeth Henderson he had four sons. James Buchanan of Auchlessie married Elizabeth Stewart and had three sons; (1) Arthur who seems to have died early (2) James died with out issue, (3) Duncan who succeeded his father. Duncan Buchanan married Grizel Robertson, and had three sons (1) Alexander who fought in the uprising of 45, and died unmarried, (2) Walter died unmarried, (3) John who succeeded to Auchlessie and Arnprior.
John Buchanan married a daughter of Patrick Edmonstone of Newton and had three sons; (1) Alexander who succeeded (2) Thomas who acquired Powis and married Catherine Abercromby youngest daughter of Sir Ralph Abercromby, (3) James died 1809. Alexander Buchanan of Arnprior an officer in the 39th Regiment died in 1845 leaving one son Alexander who succeeded to the estate. Alexander Buchanan of Arnprior died in 1848, leaving an only daughter and heiress, Catherine Elizabeth Grace Buchanan of Arnprior. Catherine Buchanan of Arnprior, heiress of Alexander Buchanan, married in 1869 John Baillie-Hamilton who assumed the additional surname of Buchanan before Baillie-Hamilton. The couple have issue.
The arms are recorded in Lyon Register Volume 39, Page 90, 8 June 1953.

THE ARMS: Quarterly, first, Gules, on a chevron between three cinquefoils Argent, a buckle Azure between two spots of Ermine and beyond these two Fleurs delays of the third issuant from as many crescents Vert, all within a bordure Or charged with eight thistles of the fifth ( for Hamilton ); second, Or, a lion rampant within a double tressure flory counterflory Sable in dexter chief an annulet Gules stoned Azure ( for Buchanan of Arnprior ); third, Sable, a chevron Argent between three bears heads couped of the last, muzzled Gules ( for Leny ); fourth, Sable the sun in his glory between nine stars,three,two and one Argent( for Baillie )

THE CREST: A sword erected in pale Proper, hilted and pommelled Or, the blade environed of an annulet Gules, Stoned Azure

THE MOTTO: 'Virtute Gladii Pari' ( Equal to the sword in valour )