Upvote:4
Definitely not "band major", Trelawny was local gentry and politically well-connected at a national level (hence governorship of Jamaica); that would have been far beneath his dignity. I would suggest it was more likely to be related to his role as one of the Scottish commissioners of customs, one of the officials of that service being "the Clerk of Port Bonds" (see era.lib.ed.ac.uk). But that's speculation, I can't see any direct evidence.