best practice using the clock code is to prefix either left or right eg Traffic right 2 o'clock
What if he says left 2 o'clock? You would be surprised how folks can get their left/right confused in a time of stress. Did it once during ambush training. Apocryphal story has it that a fighter pilot wrote left/right on the appropriate glove to avoid confusion in a fight.
I wonder what the Fleet Air Arm used?
Always used the clock, could have used the fishheads "points" I guess, as in, "two points abaft the beam, starboard side". A point is 11.25° (one thirty second of 360°)