No, it looks like I'm wrong.
I checked my own list of levels that I made while playing, and Present 13 is called "Watch your step (Part Two)". Annoyingly, Planet Lemmings just gives it as "Watch your step".
Does that count now, since I got the answer from my own list and not from a website, even though I did have to look at a website to check?
If so I will ask my question now.