The vexed question of "earlies" and doing more than 3 consecutively is covered by a NTAOCH 6/94 where the use of the word "regular" as in regular early morning duties was defined as meaning "3 weeks" or more. Incidentally the 15 minutes travel mentioned later, is defined as commencing when you walk out of the hotel main door and ending when you walk through the door of the place you normally report at.