In the last 40 years some were re-introduced and numbers have steadily climbed, especially on wetland reserves.
A few years ago we saw about 10 from a train window in the fens.
Simple QRP projects, 10m, 8m, 6m, 4m, FT8, 160m, WSPR, LF/MF, sub-9kHz, nanowaves and other random stuff, some not related to amateur radio.
My little beacon was turned on at about 0910z. No spots of me yet at 0921z.