I could not get my moms hearing aid to work so popped into Specsavers to get it checked out. Whilst waiting I noticed that they were only looking at hearing aids by appointment so had my sob story well prepared (is currently struggling in a care home without it, has dementia etc) - it did not work I have an appointment to take it back next week.
What I did find out is that if a customer has a diagnosis of dementia and has some form of proof (GP, NHS letter etc) if the hearing aid is damaged or lost the customer does not have to pay the £100 to replace/fix it. I think the £100 replacement fee has just gone up as there was a notice on the receptionists desk advising that is due to new NHS rules etc.
Hope this helps someone else.