Any help please, I have a gran with dementia, and her neighbour is too controlling

I'm putting out a plea for help because I am in a situation I don't know how to deal with. My gran, who is frail and is in the early stages of dementia, lives in sheltered housing a few miles away from me. I visit whenever I can, she has carers coming in 3 times a day, a private carer to take her out shopping once or twice a week, and some of her neighbours also help a little. But one of the neighbours seems like she's trying to take over.

She does thing without asking, and even against my gran's wishes, for example putting her heating up higher when my gran is warm enough already and has told her so. She or her husband call round in the evening and try to get my gran to go to bed even when she isn't ready. It's only little things, but it's pushy and annoying. But recently, I've found out that she's been reporting my gran to social services and safeguarding. My gran has been checked and assessed by social services several times now, and found well. I've been investigated for "possible financial misconduct" as well, after an anonymous call was made, I can't prove it was her though. (There wasn't any follow up after the first meeting, because I was able to prove I hadn't done anything wrong.) It's getting well beyond a joke.

Talking to her hasn't helped, because she is "only trying to help", and even the warden at the housing sees it that way. My dad, who is also tired of it all, has suggested I give up and let the neighbour take over, but I don't feel able to do that. I'm stressed out by this, and I don't know how much longer I can deal with it before I implode.