This is a pretty serious habit you are getting over. I don't know much about the medical system over there, but you need to A.) either go to a psychiatrist to help with a taper, or B.) see a different GP. Benzo withdrawal isn't a joke, and a doctor who is at all decent should know this.
You are going to have to explain it calmly, and be patient with them as sometimes they feel biased about the situation. Really though, you need medical help and they should recognize that.
20mg is definitely going to lower your risk of a seizure, but not your anxiety and other symptoms a whole lot. A psychiatrist will help with all the lingering anxiety with a habit like that, and help you taper at a level where you don't feel nearly as uncomfortable.
Good luck, I hope you get some help.
EDIT: Saw your most recent post, sorry I should have looked a little farther. I still agree with my above statments, but first I wouldld explain to your doctor that it is literally 10% of the dose that you were habitually taking. My doctor does a 5% down taper schedule, and weekly or bi-weekly depending on my anxiety. Although I doubt they will be so helpful to give you that high doses, but a dose of 50-100mg seems much more appropriate. And then tapering from there.