The loss of drop ins for audiology is a HUGE pain, they act like it's for efficiency but it's not better for patients who as you say end up with a wait for quite a while or trying to schedule it round work etc. I don't really trust postal repairs as they often come back not working right - BAHAs are very very hard to get right and I am very very acutely able to spot errors. Even in-person collection had a 50% "not repaired correctly rate" in my childhood. My first hearing aid technician was lovely about it when I was 5 and did not have tact, he once sent a HA back 3x before someone discovered a loose wire (analogue days).
I once used the former drop in 3x in 2 weeks when my BAHAs failed and they only had dodgy loaners which kept failing too. It was 10 min walk from work so I could go in for 9am, and get into work by 9:30. I hear nothing without my BAHA, if I don't have a working one, I literally can't do 50% of my job or much else. One reason I keep 2 BAHAs even tho 99% I use 1, is that I have a spare (although I now have 2 fully working old ones and one half working old one which I will also keep).
At least I learned Audiology can reprogram a set of BAHAs for my needs without my physical head which confuses me as the shape of my head affects the reverb, but I suspect cos they're all digital the variation between individual aids is minute (which is nice as I no longer have a 2 week adjustment period for a new physical aid) so the original my-head programming should work.
My boss hates loss of drop in audiology repair cos she's super busy, so ends up struggling to get her aids repaired without missing out on work, whereas with dropin she could turn up first thing and only have to juggle an early part of a day so do a meeting remotely from her car/hospital or move it.
My mum is a former teacher of the deaf so she knows how to do tube replacements, but she's 73 and struggling with the vision/dexterity needed to do tubes properly for her own hearing aids which she's had for 11 years now. I think the loss of places in the community someone can just drop into, is a huge loss and a mistake as it'll result in people getting out of the habit of wearing their hearing aids or feeling they're too difficult to manage.
Sadly NHS ICB commissioning groups have outsourced a lot of "basic" audiology to highstreet Boots/Specsavers/Scrivens which I remain unconvinced is a good thing for quality.