I have used NHS hearing aids for many years. Go to the Audiology department of my local hospital. They have got smaller and smaller every few years.
I can remember about 15 years ago, being on a journey with someone who was telling me how pleased a colleague was with his hearing aids which had cost him (back then) approx three thousand pounds for both of them, but felt it was worth it as they were very neat and inconspicuous. At that point I took one of my NHS ones from my ear and asked, 'Smaller than these?'. The person I was with had no idea I wore such things, and then said they looked almost identical to the ones our colleague had paid so much for.
All my batteries are supplied without charge, and if I have any problem with the aids, I just go to the 'walk in' clinic at Audiology and they sort out the problem. Last year, I went to get some new tubes, and the audiologist told me that they were no using evening smaller aids and arranged for me to attend to obtain these.
Not sure about Specsavers, no idea why anyone would go there for NHS hearing help. Sort out your nearest Audiology Clinic, and once these aids are in place, she will quickly wonder why on earth she waiting so long to get them.
May need to get used to them over a few weeks, wearing them an increasing amount of time each day. I put mine in as I get out of bed, and they stay in place until I go to bed.