Since Shepherd Neame was established in 1698 and Trevithick's stem engine not built until after 1800, the hop-pickers from London are unlikely to have arrived en masse in Faversham from the earliest days.

Therefore the earliest celebrations of the hop-harvest are likely to have been accompanied by local merriment and song - viz the tradition is of folk music and dance.

Incidentally, I've been a hop-picker.