Anti-Scottish prejudice had flourished throughout the eighteenth century, sharpened by the two Jacobite rebellions and the unpopular ministry of Lord North, the Earl of Bute, and more recently by the cultural power of Scotland most tellingly embodied in the great reviews. The Scottish Lowlands introduced modern farming practices earlier than most areas of Britain, which made Scottish estate managers particularly popular in this period. JA may be remembering Edgeworth's "Ennui" (London, 1809) in which Glenthorn's land agent in Ireland is the exemplary Scotsman M'Leod. On Glenthorn's first meeting him 'national prejudice heightened the prepossession which circumstances had raised. Mr. M'Leod was not only an agent, but a Scotchman, and I had a notion that all Scotchmen were crafty' (Ch. 4)
The Cambridge Editions of the Works of Jane Austen (2005) Richard Cronin, Dorothy McMillan (p. 556)