It's possible though unlikely Camiila is correct about a certain school in London - London has the huge advantage of lots of potential qualified employees within commuting distance, in a way that other places don't (possible exceptions of Wolverhampton and Bristol).
It's certainly not common.
Radio aids etc going unmaintained and unused is a common problem - I have to admit I rarely use mine as its such a bugger to set up and only works in certain kinds of meetings, but also they can be terrifying for kids - sound goes direct from teacher into child's head, teacher suddenly shouts... My friend used to get into trouble at secondary for not using it but her parents supported her, especially as the teachers weren't doing things like writing topics or key vocabulary on the board, nor providing reading material in advance, nor, most importantly, dealing with bullying.
More deaf awareness would be great. A key point is the effect of background noise and its much more of a problem with hearing loss. Another is how few people use 'pure' BSL, as so many older people and youth influenced by texting etc use much more SSE, and how regional BSL is (which I think was the key point that scuppered the GCSE). And BSL is rather like Welsh in that people discussing very technical stuff tend to use English. I had a terrible AtW assessment once where the assessor's only suggestion was I should learn more BSL. For physical reasons that would be hard, it wouldn't help for the five or so years before I was good enough to use a terp, but most importantly the assessor's terp pointed out there were probably no terps who could interpret my job for me. So I use speech-to-text reporters.
Who are a rare and underused resource for people who are deafened or deaf and have good English. I'm sure a STTR based in hospitals to ensure elderly and other deafened people understood their consultations and could take a transcript home would be a good use of money.
I'm sure my PIP assessment was decided when they said surely with STTRs I wouldn't have a communication problem and I handed them a file of all the calls my partner had had to make, the emails confirming Atos only offered BSL, and emails cc'd to my MP explaining the Equality Act in words of one syllable. No, getting STTR a few times a year is not a magic solution.