Phone suitable for hard of hearing mother with dementia

[MinglyMadly]

My dm is struggling to use the phone she's had for many years. She's hard of hearing and always had to put the phone onto speaker phone in order to hear properly (it's been that way for many years and pre her dimentia diagnosis).

I sourced a phone that had an extra volume option but a button had to be pressed after answering in order to activiate it and she can't cope with that.

Could anyone recommend a phone that is extra loud on immediately picking up the reciever?

To clarify this is a landline we are after, not a mobile phone .

Check RNID as they have a link to a shop that sells phones which may be suitable.

We had this one for my FIL