About 2 years ago I developed a medical condition that I feared could lead to a med discharge, in the end it didn't, but a couple of things came to light.
Once you get downgraded you'll get an employment review board and then the med board. They'll decide the disposal action (or not).
The main point to note however are the terms of your discharge. You can be medically discharged or you can be admin discharged for medical reasons. The latter being much cheaper and not attracting a medical pension and if you haven't passed an IP point, no pension, though I suspect you will have past that point. Quite how they decide I never fully pinned down but it seemed if it was service related you got a med discharge, if it was something you developed out with of service causes you got the admin discharge.
I may stil have some of the info I dug out. I'll check later.
Also AP1269 lists med conditions and how the RAF views them, look in that to see what it says about yours.