Seems like metal detectors are a popular passtime in the UK.
They’ve been invaded before. (and its happening again.)
Metal detecting is what I want to do if I’m able to retire one day. Some people like golf, I’ll metal detect.
:^) I once had the acquaintance of a British-born character who seemed to have an unusually diverse job history (ahem), and professed to having picked up a lot of successful techniques for locating buried Roman hoards (presumably last minute attempts to hide property before fleeing). Dunno if that part was true, but he knew some oddball field archaeology, like the "birdfoot" method of predicting the Roman and post-Roman paths to river crossings. He also used to holiday in Gibraltar, claiming to pay for the trips by free-diving to a deep spot where earlier vacationers tended to have lost Rolexes etc.