Those parts of Kent are fairly deprived. I saw one notable local stupidity instance recently, but not loads like there were with Manchester a little while back: www.kentlive.news/news/kent-news/five-party-organisers-face-fines-4669639
It's worth noting that cases near the coast in Essex are rising too, though not as sharply. The more I look at maps over time, the more they look like they're tracking weather fronts until the virus increases to a high enough level to sustain itself in a town or city and sits there. I think in years to come the enormous impact of weather on covid transmission will become clearer. I can't prove any of it, but sharing the thought, sorry.