Visible crew/equipment: When Blackadder and Melchett leave to go visit the Queen and they close the door, the boom mike is visible in the upper left corner of the screen. (00:05:05)
Visible crew/equipment: After Blackadder has pushed Queen Elizabeth into the closet and sits down at the table, Percy "coughs". When it cuts back to Blackadder, you can see the boom mike above his head. (00:17:00)
Visible crew/equipment: When Blackadder is about to leave Captain Redbeard and Redbeard says, "So you do have some spunk in you," you can see the boom mike pop into picture in the upper right corner of the screen. (00:12:50)
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: 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: 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)
Answer: It's not known what Baldrick's first name is. Sod off is a way of telling someone to go away or get lost. So when the kids say, "We know. Sod off, Baldrick," what they were really saying is, "We know. Get lost, Baldrick."
I think you missed the joke.
lionhead