Thanks Moonwillow!
No way about rats! I ended up using a poster and a PNG graphic of one. I've been using this spawn commands list some-commands-to-spawn-objects and I did I Ctrl+F but couldn't find any rats. Guessing that list is a little outdated. . .
I've actually found a map using the seed "Australia" - it's got a real potential. Beautiful harbour location, flat lands but a little hilly, nice forest too. I'm going to take my first build as a learning curve and this second one is going to be the "serious" one.
This game is awesome