Would CAMHS write you a letter for your local housing authority to get rehoused?
Various people at my local NAS have managed to get rehoused due to an autistic child needing their own room. Another one is a garden requirement for a trampoline to physically work of steam. Can help enormously with ADHD if thats one of his comorbids. Our NAS is big on trampolining. Its a great parallel activity that the DC can do together but individually.
We have bose noise cancelling headphones, the chunky over ear ones. DD (8) said after party day at school that they're her favourite thing in all the world because they make her feel okay when everything doesn't feel okay. DS (16) says that ear defenders are really uncomfortable after a while and when you're feeling overwhelmed and everything feels worse it hurts to put them on. He does keep a fold up pair in his school bag and they do get used but I think its a way of him signalling the teacher all isn't okay without having to verbalise it. He also has bose wireless ones, before the wireless ones came out it cost a fortune as he'd twiddle the wire and they kept breaking. £30 a time for a new wire.
DS2 (13), not autistic, has just had some Xiaomi Redmi Airdots, in ear wireless headphones. They're not bose standard but they cost under £20 off eBay and DH was so impressed we got him a pair too. They are what I'd call semi noise cancelling. They could potentially be a help if sensory issues don't cause a problem with the in ear. DS1 (16, autistic) can't tolerate in ear, especially when he's discombobulated.
With a diagnosis are you now applying for DLA? It helps with these things, was a game changer for us. It has a knock on effect on other benefits and if you're earning under I think £110/ week you can apply for carers. Then evidence of disability becomes something that can be used to go in free places as a carer.
Another potential place to get some financial support with things that would make life better is the family fund: www.familyfund.org.uk/
Again people I know at the NAS have applied once every twelve months and got typically around £500 a time to pay for essential equipment like tech. Ipads for speach and language programmes, headphones, butlins breaks also been applied for.
Have you come across weighted blankets. Some people I know with deep sensory issues find they help them feel more grounded and comfortable. There can be purchased or there are various tutorials/ you tubes, blogs about making your own.