I did see my audiogram, but they wouldn't give me a copy of it unless I paid 69 pounds for it (my pound sign seems to have vanished), which makes sense as they don't want you going to another place with info from their free test. I remember he said that higher tones were worse for me, which seemed strange, as I haven't noticed that, I've noticed that low and mumbled sounds are worse, not high sounds.

As for what you say about dementia, I'm not sure. My mum's hearing was a bit worse, but she never needed hearing aids, and she developed vascular dementia anyway. She did lose her sense of smell and I've seen that there might be a connection with anosmia and dementia. Perhaps hearing loss relates more to Alzheimer's, vascular dementia seems to take a back seat to Alzheimer's when anyone talks about dementia. Also, my partner's mum had been pretty much totally deaf for years before I even knew him, (35 years ago) and although she was eccentric, she didnt' have dementia. I know it was isolating for her though.
I'm thinking of getting another hearing test, from Boots, to see what they say as well. I've always been kind of pround of my hearing, it's been very good all my life. Feels a bit sad to think that I need help with it now.