After he left the House of Commons, Stewart was created a life peer as Baron Stewartby, of Portmoak in the District of Perth and Kinross on 20 July 1992.[3] He sat in the House of Lords until his retirement on 12 November 2015.[4]
Interest in numismatics
Stewartby's interest in Scottish coins had started when he was a schoolboy. Noting the lack of a complete book on the subject more recent than Edward Burns' 1887 work Coinage of Scotland, he was encouraged to write his own. The result, The Scottish Coinage, was published by Spink and Son in 1955. The preface, dated December 1953, gives the location as Haileybury College, Hertford, which he attended from 1949 to 1954, as a member of Allenby House.
In July 2007, Stewartby's collection of antique Scottish coins dating back to the 12th century and worth an estimated £500,000 was stolen from his home near Peebles.[5] The coins have yet to be recovered, and in November 2008, a £50,000 reward was offered for their return.[6]
A lymphad as in the shield between two fleurs-de-lys Or.
Escutcheon
Or a fess chequy Azure and Argent between a portcullis with chains in chief and a lymphad sails furled oars in action Sable flagged Gules in base all within a bordure Azure a label of three points Gules.
Supporters
Dexter a stag Proper attired Or gorged with a collar engrailed Gules sinister a lion Proper gorged with a collar engrailed chequy Argent and Gules.