A wee bit more "research", then, though not specifically/only for"Craigie Hill"; the word "beagle" was actually a term for, well, bailiffs or similar agents (Robert Burns in one of his letters - 1780s rather than 1790s - refers to the Kirk Session as "the Holy Beagles"). Nevertheless, the thought of "literally hounding" people from the places "where born and reared [they'd] been" is of course entirely appropriate, and whereas the majority of a modern audience will most likely imagine exactly such a scene, I'm pretty sure a contemporary one would have appreciated the poet's parallel.