Second side note: on the line "W–– govern'd in a B–– Reign";
I'm not entirely clear who is referenced here, but Higgons and his family were well-known Jacobites who held fast to the House of Stuart after the Glorious Revolution and the installation of the Hanoverian dynasty with George I.
My best guess is that "W" is Robert Walpole, who governed under "B", being King George (either the First or Second), Duke of Brunswick-Lüneburg. Walpole was a Whig and the Jacobites were associated with the Tory's.