I had been looking into this for the last while and the latest is that the MCA has been encouraging me to go for the medical. An ENG1 is a no-no but the ML5 is a possibility.
The crazy thing is that I go to sea and have to get special exemptions from the ENG1 to do so.
Anyway, when at the doctor for a seagoing medical a few weeks ago I specifically asked about ML5's. He contacted the MCA and they said that it wasn't an outright NO but depending on circumstances it may be passed, possibly with some restrictions to area or distance. I have been encouraged to apply, fail, then appeal the decision to see what may be decided.
I may have some advantages in that I am a recreational diver and work at sea already sometimes but will see what transpires over the next few months as I get around to it.
Basically there is no definitive answer yet. BTW I don't like being called disabled, Diabetes is not a disability but a medical condition