Trouble partner back on the scene!

Hi all hope you are having a lovely sunny bank holiday weekend.

I have a little scenario I'd just like to know where I stand. We had a couple move into a property a year or so ago. Had a few bits of trouble with the male half of the couple getting drink and causing noise/shouting etc and upsetting the neighbors. Eventually he buggered off and we re signed her back up on a new AST after getting a signed letter from them both to quit the first agreement (it had gone onto rolling). Mrs is now halfway through the new 6 month AST.

Anyway as the property is just round the corner from us its pretty easy to spot comings and goings and recently I have seen Mr in the village a couple of times and assumed he must be back in the area. Well today I have seen Mr and Mrs together. I cant confirm if he is back in the house but if he is where do we stand? Obviously its no business of ours who Mrs is with but theres no way we would have Mr back on the AST.

I guess could issue something at the end of the AST if we did get any issues? Either way we'd like to know where we stand on what we can do about Mr trouble.

Cheers!