Why Not
Rather than ground the aircraft the RAF should order the Co Pilot to fly the aircraft manually in the cruise and the Captain should shout at him/her if the aircraft deviates much from the flight path...a small stick could be issued to aircraft Captains if shouting fails to have the desired effect.
Of course the Captain will need to have natural breaks and the odd snooze so we will need to re introduce the Flight Engineer onto the Voyager flight deck to do the shouty hitty stuff when the skipper is unavailable.
Flight Engineers quite handy to have about. Perhaps the RAF have forgotten that.