Ah, cool. thanks... And I see an entry in the documentation now too! Super! I'll switch out my multiples-of-11-hating shonky random alg for something smoother :)
random(n) would also be handy, but it's not there at the moment.
Another useful command is :execute_one_at_random{}. There's an example in the doco. I used this in combination with chance(n) to get the troll in 'Seeker of Magic' to do one of ten different things at random 30% of the time.