Looks like there’s one mine left operating at any real capacity. ~100,000 tonnes a year.

https://en.wikipedia.org/wiki/List_of_coal_mines_in_the_United_Kingdom#21st_century

Much of that mine’s output is apparently ground down for carbon filters, although it used to be used at a nearby steelworks that I think is now shut.

Domestic use of coal is pretty rare, most people not using gas or electric are using wood burners.