Visible crew/equipment: After they come out of their exam in the corridor, Duane and Stewpot are asking Pogo what he thinks of Christine, there is an overhead mic in shot above Duane.
Episode #2.9 - S2-E9
Visible crew/equipment: The SAG committee is having a meeting with the headmaster in his office when Mr. Llewelyn is talking to Jessica. A shadow of the mic can be seen on his jacket.