This is the link. It applies only where the child is at risk of harm, and the person has contact with them. I suspect it's for offending that has involved an actual physical assault, unless the perpetrator is a partner or something. I don't know, however. But the wording does imply that, because they need to balance the risk of offenders constantly having to move, and therefore being harder to monitor.
I think there's more of a risk in worrying about the creepy guy down the street and nobody else, honestly. Child sexual abuse is incredibly common and most of the time people aren't charged or convicted because the child doesn't disclose, or there isn't enough evidence to do anything when they do. Most abuse happens when someone you know grooms the whole family. It's usually someone you know, and probably trust. That wouldn't be this man.
Children being attacked by strangers is very, very rare, thankfully. Common sense, and vigilance around their behaviour with people you know is the best protection.
The really hard thing is that you can't protect them completely without also harming them in terms of learning independence and trust in others as they grow up. It's like all forms of confidence tricks; the criminal relies on the human need and instinct to trust other people. And that need and instinct is also essential as we can't form relationships without it.
There's a really good book, often mentioned on Mumsnet, called The Gift Of Fear. It talks about how we prioritise manners to such an extent that kids, and adult women, are scared more by being thought rude than by potential assault. I think teaching our kids that their bodies are their own, and that it's okay to say no and to remove themselves from situations that make them uncomfortable, and that it is NOT rude to do so, but rude of the adult to place them in that position, is key.
We can't mind-read, and know who around us poses a risk. We can only arm our kids against that risk.