I have a bell in the workshop that I used to rent off bt,although soon got around that ,anyway now they’ve switched us to internet phones,it doesn’t work,so it’s very hard to hear,and I probably miss a lot of calls.
A house my mate bought had a call every night to the house line, he had no phone connected so never under stood why all the lights flashed in the house. The original owner was hard of hearing and had an induction loop and a device too trigger through the lighting circuit. He opted for the full rewire
My Dads were £2000 but come with a lifetime guarantee. They were partly funded through one of the military veterans groups as his hearing loss was proven to be caused by years of gun training whilst serving in the forces.