Visible crew/equipment: In the shot after Blackadder has read up Baldrick's votes a microphone is visible in the upper right corner. (00:18:15)
Visible crew/equipment: During the conversation between Blackadder and Baldrick, as Baldrick explains what he spent the £400,000 on, we can see the shadow from the boom mike moving on Blackadder's fur coat. (00:28:00)
Revealing mistake: When Baldrick is on the metal spit rotating by the fire, the fire is just a light up board.
Revealing mistake: When Blackadder lifts the huge turnip it looks really light. A turnip that size would weight a fair bit.
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