And of course you are right!
Since I was intested in the Mac platform, I missed the clue that the Softlearn sim supports Windows _and_ Linux. I downloaded the trial version, ignored the install script and after a little fiddling with the java command line I had the exam simulator running on the iMac

I guess I'll buy the full version.
They should make more of a feature of the fact that it's a Java/Swing app and runs anywhere.
Are any other exam sims Java based?