Even if he's just trying to provoke a reaction he should be free to do his 'audit' in a free country, he's not doing any harm.
I was told by someone a few years ago who had friends in the local police that a lot of the older experienced officers were taking early retirement in dismay at how the 'force' was going, basically lots of rookies fresh out of university being brought in who think that Twitter TOS are the laws of the country, not helped by 'woke' courses that they are forced to attend. Older officers who know the law and traditional policing will also push back if they're asked to do something they don't agree with whereas the rookies will just do whatever they're told by seniors. It's probably why we have the situation we have today where laws are forced selectively, hold an Antifa/BLM protest at the height of the pandemic and police stand and watch, even kneel at you while you tear down statues and throw things at them, hold an anti-lockdown protest without any criminal damage occurring and they immediately come out batons swinging. I'm sure many of the police are very good people trying to what they think is best but institutionally there is something rotten about them, I think they have become too political at the top and it's filtered its way down.
Hopefully they will have him marked and give him some grief at every opportunity, he needs a holiday in Russia to see just how well treated he REALLY was here in the UK. If you go looking for bother eventually you'll find it