What I found useful with dealing with a shit ndn was to always have a recording device in my hand as I was coming and going. One, this worked like a charm for her not approaching me, but two meant I was ready to record what she said if she did (I got her yelling at someone else in the end and this was great, not least as it was impartial evidence (ie neither knew they were being recorded)). Thus I would recommend having a phone, camera or some other device always in your hand when outside. I had a covert recording 'pen' that I used for mystery shopping. Make sure you test it first. That way if he starts hassling you because he thinks you reported him, you tape it and it becomes positive evidence. Legally I'm not sure what the rules are, but the police seemed to accept the recordings I sent them. The police class someone calling you names etc as an offence, eg intimidation.
If you don't have your device, or if you'd prefer it legally, report every word you can remember via 101. Each time if necessary.
Recording noise eg music etc doesn't always pick up, frustratingly. Even on official council recording equipment. Even if it's really loud to you! That's why you have to emphasise that you are worried/fearful etc.
If you speak to the other neighbour, take care to not say anything that is seen as harassment. Ie encouraging someone to complain, even if someone else is behaving shitly, could be seen as that. Make it sound as constructive as possible, eg ask them if they can park all over his drive as a solution (as sometimes you have to go out at short urgent notice and are blocked in). Imply to them that you are trying to find a solution and would like not to pursue it. Yeah, he might still call you uptight, but you can't fix stupid.
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Shit neighbours - I have so had enough. Problems here for years, including a really bad history with ndn (she did yell in my face for 15mins the other week, but at least she isn't having people round at the moment). But currently surrounded by them on this estate (although with the capacity to get much worse, eg if the Ndn kicks off again, or in the continuing lottery that frequently changing council tenants in a block of flats/street are). All of them are only interested in pleasing themselves. And any of the 50% quiet decent people here who complain get called 'uptight' (at best), and badmouthed by them all (which is just horrible, as you've found). Fuck 'em.