Hi Op
You definitely need to get someone knowledge about housing neighbour disputes law and rights ,
Have you tried citizens Advice bureau, in the past?
We're they any use /beneficial at all?
What about trying a local political Councillor to speak up on your behalf, about your issues , to relevant Agency/Authority,
Also get in touch with A local MP, aswell to support be your Ally in this shit situation,
They can do very similar kind of role as Political Councillor,
Thinking about it, they can do more than that potentially too.
The more people on your side who have your back, fighting your case,
The better emotionally it will be , Obviously be and less isolated you will feel,
So will feel more stronger emotionally to deal with Crap people like this ,
that you have unfortunately had misfortune to come across
I think your Next door neighbours and mates
Sound like bunch of Arseholes /Head cases really...
I suffer with health problems too
Rumertoid Athritis Athritis and OestoAthritis
This would be one of my nightmare situations to deal with every day..