Visible crew/equipment: When Blackadder calls for Baldrick and asks for a raw turnip, as Baldrick enters, you can see some shadow moving on the left of the screen. It's not Baldrick's shadow and there's certainly no one else in the room that could make that shadow. (00:13:55)
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)
Answer: The closest we ever get to knowing his first name is in series 3, when he claims it's "Sod Off". Blackadder asks him in series 3 where this came from, and he replies "Well, when I was a kid, living in the gutter, I'd go up to the other kids and say 'Hello, I'm Baldrick'. And they'd say, 'Yes, we know. Sod off, Baldrick.'" The S in this series is likely a reference to that, but it's not addressed, and given this Baldrick is clearly different from the series 3 Baldrick, we can't draw a direct link.
Shay