If you have Addison's disease then surely you take extra steroid before you exercise? If your bloods are low like that then it would indicate you are not on enough steroid. (I have Addison's as well as diabetes) If your cortisol levels are causing the low sugars then glucose will not rise your blood sugars. Back to your licence you are not allowed to drive if you are hypoglycaemic and have needed help twice within 12 month also if you are unaware of the hypos then it's a def no no for driving. Your licence as is your ins is invalid. It's not up to the consultant or anyone else to tell you to inform the dvla it's down to you. Hope you sort yourself out soon.