I think that old chestnut about MEDA availability isn't all that relevant in the current era. There simply aren't that many aircraft airborne at one time these days - and in Scotland Glasgow, Edinburgh and Prestwick are all open 24 hours. You can make cases about armed aircraft and handling fast jet types etc, but it can be done. As for the heavies, they can carry fuel for further afield alternates if required.
It may not be ideal, but lack of diversion airfields is not a valid reason for keeping somewhere going, specially given the projected size of the RAF's fleet.