You can't just fire someone, in an instant, there are are a bunch of boxes you have to tick, you know
Stop saying this. If you have evidence you can fire someone straight away for gross misconduct.
As i have said before, we have 'indecent behaviour' as part of our description of gross misconduct. If someone who we employed did what this guy did, and said it was filmed at work, he'd be sacked instantly. Even if it turned out that it wasn't in fact at work, the fact that he said it was, and that his place of work is easily identifiable would mean that it would have been indecent behaviour AND bringing the company into disrepute.
I imagine this guy has lots of dirt on other employees which is why he hasn't been sacked straight away.