????? I suggest that's advice you should take.
I have been properly monitored since 1985. Over the years, competent monitoring by specialist doctors has found certain problems and they have acted accordingly. If I had only seen a high street optician and the service about which I have complained, I suspect I'd have been totally happy until going blind.
The public being told that diabetic retinopathy is being checked would be unlikely to realise that there are many other eye problems that can be linked to diabetes which the "service" does not check for. By thus, in some cases, creating a false illusion of there being nothing wrong, this limited low standard service is, in my view, extremely dangerous.
Regarding your own condition, you made a very big mistake. Diabetic retinopathy doesn't go away. It may have reduced but as far as I understand it, the advice you describe is just plain wrong. I strongly advise you to have occasional eye clinic checks before it's too late.