You don't need to read PMOT to work that out. It's quite obvious reading through D'Urfey's "Pills" and the many publications that jumped on his bandwagon. Or as many of them as you can stand without feeling slightly sick.

There seems to be a cycle here. The first Irish tunes to be fashionable in Britain date from the 1580s. "Scotch" tunes with D'Urfey, Purcell etc in the 1680s. Highland music takes off with the Gows and Patrick Macdonald in the 1780s. Highland music hits a peak again in the 1880s coinciding with Queen Victoria's infatuation with men in kilts. "Celtic" music post-Alan-Stivell in the 1980s. Maybe we should get the astronmers looking for an undiscovered tartan planet with shamrock-shaped moons.