Visible crew/equipment: After King Richard has been crowned, Blackadder, Baldrick and Percy return to their chambers and start cheering. When Blackadder says "We're safe, and I am a prince of the realm" you can see the boom mike move up in the right corner of the screen. (00:16:50)
Visible crew/equipment: After Blackadder has his haircut, the camera zooms in on his foot. He lifts his foot revealing a red tape marker on the floor. (00:21:50)
Visible crew/equipment: When Blackadder returns to the castle after rounding the sheep, Prince Harry says "Ah, Edmund." Blackadder then walks behind one side of the wall. The shadow of a boom pole can be seen on the right side of the wall as he does this. (00:02:40)
Visible crew/equipment: When Harry tells Blackadder to be in charge of the welcoming of King Richard's return, as Blackadder turns around and walks against the fireplace saying "12 months of chasing sheep.", if you look closely on the top of the fireplace you should be able to see the shadow of the boom mic moving. It's quite hard to see, but it's there. (00:03:45)
Visible crew/equipment: When Harry comes to see Blackadder and asks how the entertainment program is going, Harry says that St. Leonards himself was a eunuch. As it cuts to Percy agreeing, you can see the boom mike move right above Baldrick. (00:08:40)
Visible crew/equipment: Just after Edmund, Baldrick and Percy get up from sitting by the fire, and before the line "The Black Adder will be King next", the shadow of the boom mike can be seen on Baldrick's hat - it moves upwards quickly so can be hard to spot. (00:06:15)
Visible crew/equipment: In the final shot where Percy and Baldrick have entered the room and said their lines, as it fades to black the crew can be heared applauding.
Answer: Tony Aitken played the Balladeer. Blackadder wants to kill him because he annoys him and usually sings songs about what a fool he is.
Captain Defenestrator