Bloody hell, this sounds horrendous. It sounds like you already have a plan of action and will be leaving him to fester in his own misery, but for what it's worth, could the other CAB - Citizens Advice Bureau - be worth getting in touch with? Their site has a section about discrimination in rented housing, which sounds like it could definitely apply here. I've not used their services but looked into it when my agency were being dicks a few years ago, might be some useful info here:
https://www.citizensadvice.org.uk/housing/discrimination-in-housing/checking-if-its-discrimination/if-someones-harassed-you-in-housing/I'll also add to the cacophony of voices suggesting you try to record this twat if you can. I had a horrible night a couple of weeks ago (on a Tuesday night), when my upstairs neighbours - four guys who I'm guessing are about 20 - came home at midnight and were stomping around, talking loudly and shouting with their balcony window open, so I could hear everything word for word.
After a couple of hours of being unable to sleep, I went up and knocked on their flat door and asked if they could keep it down a bit as I had to work in the morning - they were a bit hostile, saying they were just talking and I couldn't expect them to not talk in their own flat. I said I understood it wasn't their fault that the sound insulation between the floors was so crappy, but it wasn't my fault either, and I had to be up at 6 regardless and didn't think it was unreasonable to ask them to keep the noise down at 2am on a weeknight. (Not saying that people with 9-5 type jobs should be treated as a priority - I haven't got a clue what they actually do, I don't think they're students but I assume they don't work during the day - but it's not like I've ever knowingly disturbed them, and ultimately if you live in the top floor of a shared building you have to be respectful of the fact that people can hear you, whatever your schedule is.)
They sort of relented, I went back to bed, but about an hour after
that they'd started playing music (the same shitty techno they always play with the bass cranked up) and were banging around. I went back up and knocked again several times, loudly, and they ignored me. I left a note on their door saying I'd complain to the landlord if it carried on, and went back to bed. When I was back in my flat they'd
really cranked it up and were going absolutely mental, whooping and screaming and stamping on the floor and throwing stuff, or it sounded like it anyway. This was still going on when I had to leave the flat for work at 7am.
There was no way I was getting any sleep by that point so I just calmly filmed it on my phone (showing the clock, and also my bedroom door rattling in its frame every time they hurled themselves around the room upstairs) before going to work on about 10 minutes of sleep. I sent the videos to my landlord the next day and thankfully he gave the main tenant a talking to, threatening to call the police if it happened again, and it's been blissful silence ever since. It doesn't sound like your landlady would be as accommodating sadly, but it's never bad to have some sort of evidence with a time and date stamp on it.