Mikefnz:
I bought this phone and will update once it arrives and is tested!
https://www.noelleeming.co.nz/p/uniden-sse30-big-button-corded-telephone/N145439.html
And it works - in all senses of the word.
Technically it works, but more importantly it is simple and does what an 89 year old woman with dementia expects. The phone rings, she picks it up and talks; no buttons to press. When she needs to phone someone she picks up the phone and presses the simple big clear buttons.
Technology is great but we need to make sure we don't leave some people behind.