Barry, if you are still around...
Abusive, aggressive, disruptive people are dealt with mostly by reassurance. It comes from fear. If possible, that person will be guided to their room away from others, or if that isn't possible, other residents might be led away.
Thankfully, for the last couple of decades, you are no longer allowed to medicate somebody, just to make them easier to "handle", but often those people will get meds that benefit them, such as anti-anxiety etc. I have seen a couple of occasions where police, and/or Social Services are called- to keep others safe. And in 27 years, maybe 5 sections. But in each case, they had something extra to dementia- aspergers, schizophrenia, undiagnosed psychosis...
Very often, once people are settled, have at least a slight routine and feel safe and protected, their behaviour settles as well, so it gets less challenging.
I would look at and speak to any specific homes you are thinking of. But everyone has to be trained and qualified in challenging behaviour now. It's dealt with by kindness.