From the Page http://www.picaxe.com/Teaching/Other-Software/Scratch-Helper-Apps/ the link http://www.picaxe.com/downloads/s2bot/MacS2Bot.app.tar.gz only gives you version 0.1.0 which has no options for Lego Boost.
The software on the link http://www.picaxe.com/downloads/s2bot/LinS2Bot.tar.gz...