You are NOT being unreasonable. I haven't read the thread.
I live in social housing and had to move twice in the recent past because of abuse, harassment, and crime perpetrated by neighbours.
First of all, document everything right from the get go. Video record and audio record absolutely everything, then save it, report it, log it, to your landlord (Council or HA) every single time at the time. I have only ever made progress in such situations by video recording everything.
Also report it to the police - you can use the online reporting system if you don't want to have to ring and speak to disinterested morons who will lie to you and tell you there's no crime to answer.
Also be aware that the police and the housing will try to harass you by suggesting that you're being unreasonable, that you're complaining and no-one else is, blah blah blah. They will try to play you off against your neighbour and they will 'let slip' to your neighbour that you've complained. This is what they do every single time without fail.
The reality is that they have placed you as a vulnerable adult with a tiny child in a dangerous situation. And you bet your life they already know that. So, as soon as you start complaining, in reality the housing start defending themselves against your rightful allegation of that failure.
Eventually, they're going to have to move you again -or- evict the problem tenants. As they rarely / if ever evict problem tenants, you might as well get in the frame of mind that you'll be moving again.
Take legal advice, go see your local Councillor and go see your local MP. Check if there's a Tenants and Residents Association (TRA). Tell your GP - make sure the impact to your physical health is noted. Make a note of every single way this is affecting you and tell them. Tell everyone who will listen - do it by email and in writing. Forget about phone calls, phone calls don't 'exist' and anything they say verbally is utterly meaningless.
Connect with as many like minded people as you can on this issue and get support. Be careful when discussing with neighbours that the housing will say this is you group harassing the problem household, so do it discretely and be careful what you say. For example, do say 'I feel terrified for my personal safety as my neighbour is hanging out of their window screaming threats at me' - do not say - 'my neighbour is effing insane and I think they're on drugs' or you'll be landed with a warning.
Good news is you have your tenancy now. You will keep it, even if it means you have to move. Think strategically.