Not quite the same thing but when I started riding again after losing the use of my right arm and hand I had to take a driving test in an adapted car to get my car licence back (and the one car test included the m/bike category). No additional premium for insurance.
I was advised by the NABD (Nat'l Ass'n for Bikers with a Disability) that under the Disability Discrimination Act insurers are not permitted to load premiums for any disability because if you're cleared as 'fit to drive' you are as fit to drive as anyone else.