I'm including a diagram because I know what you people want. And there is backstory, but I'll try to keep it brief.
Moved in 2 years or so ago.
NDN was always reclusive and quiet and never spoke if we passed each other in the alleyway that our two front doors open onto.
When we moved in, it was me, my then DP and my DD(now 12).
ExP and I split up last year. My house, so DD and I are still there.
Since ExP left there have been various incidents where I've been outside in my garden and heard NDN swearing at me from behind the fairly high fence that separates our gardens. Things like 'you stupid fat cunt', 'why don't you just fuck off?', and other variations on that theme.
Once I took a phone call sitting on the steps outside my front door, talking quietly. There's not a lot of privacy in my house due to layout and I needed to have the conversation but didn't want it heard by a little pitcher. While I was on the phone NDN came and stood at his front door, opposite mine, and stared at me through the frosted glass and let off another volley of full on swearing. To be fair, I took his point at the time, if not his approach, it was the evening, though not late and maybe it was annoying to hear my chattering, though I wasn't loud, if anything I was quiet, bearing in mind that I was trying to avoid being overheard. But it seemed OTT.
Since then, I've tried to avoid him as much as possible, but I catch him occasionally glaring into my kitchen window, the only part of the house he can see into. I've seen him curtain twitch when we come and go during the day sometimes too.
I also once heard him swear about 'that cunt setting off his outside light', which we do if we come home in the dark, as it's outside his front door, it's a narrow alley and there's no way we can avoid the motion sensor.
But last evening there was a bit of an escalation. I went to put rubbish in one of my bins. As it was empty and they were bottles, it did make a small noise. His back door was open and I heard him yell 'Fuck off'. Admittedly I exclaimed 'What?', but more like a startled reaction than anything else. He stuck his head round the door and glared at me, looked like he was about to say something, but I carried on putting my bin out and by the time I turned round he'd gone in. I went in, went to my kitchen, at which point he appeared in his back doorway and glared and glared at me with the angriest look I've ever seen. I turned my back on him and carried on cooking. When I looked again he'd gone.
He is elderly, and tiny, and I'm not at all physically intimidated by him. But it is unpleasant, and I genuinely am not sure what I have done to deserve this level of vitriol. It is unpleasant to live next door to. He has never said anything to my DD, it seems to be me who has given him the rage. I am almost certain, from other behaviours there is something mental health related there. I know, I know a lot of you are going to tell me to log it with the police, and I am preemptively taking that advice on board, and mulling it over, but I don't know, he's not a physical threat, and I'd rather calmly deescalate it if I can.