Two years later he was promoted to a Personal Chair, the first awarded by the University of Stirling. He took early retirement in 1980, having worked part-time for a few years before this due to ill-health.
Dalawang taon mamaya siya ay itaas sa isang Personal Chair, ang unang na iginawad ng University of Stirling. He took maagang pagreretiro sa 1980, sa pagkakaroon ng nagtrabaho ng part-time para sa mga ilang taon bago ito dahil sa sama-kalusugan.