Digital Economy Act 2017 increased the already-existing penalties to max 10 years in prison for copyright infringement - which you technically commit every time you fire up BitTorrent without blocking upload. The same act (and its predecessor 2010 bill) compels ISPs with over 400k subscribers (i.e. all the big ones) to monitor subscribers for such activity.
The fact that prosecuting authorities tend to go after distributors rather than consumers is simply due to a value-for-money calculation. There is no formal or informal decriminalisation of consumer piracy, if they could find a cheap way to go after everyone they would - and they likely will, sooner or later.
if we've had laws such as that since 2017, and they were being enforced, you would have heard of people getting sentences, or even fines, right?
surely you can find stronger evidence than the police taking the unprecedented step of contacting - contacting, not arresting, or fining - a few tens of thousand in one region of the country?