Harry Bloomfield wrote:

West of Garforth, today 20:15 on..

Planefinder.net does show a single aircraft arrive from the south, swizz
around for a bit (doesn't look like 40 circles on screen, but don't know
what resolution/interval it records at)

Seemed to spend longer over Huddersfield earlier in the afternoon

https://planefinder.net/flight/UKP155/time/2021-04-17T19:15:00.000Z/speed/20

aircraft is G-POLV, which is a national police plane, so that seems to fit

https://abpic.co.uk/pictures/view/1730258
https://twitter.com/npasnortheast/status/1262633327934222336?lang=en