Is the LEGO Mindstorms Education (not Home, not Scratch based) Edition for Mac OS gone? I am starting a robotics and programming club with some 9-12 year olds and for the past week I have been developing activities using my Windows version of LEGO Mindstorms (the education / teacher edition) on my Windows 10 PC.

In the classroom I will be using we have an assortment of Mac OS Laptops (thankfully not running Catalina). I wanted to get the same Education Edition for the Mac because the Mindstorms Home Edition is hideous and lacks many features, plus I have developed a lot of educational resources that depend on it.

However, now that LEGO seem to be testing the waters with the new Scratch based Mindstorms for Mac OS, the Education / Teacher edition of the classic LEGO Mindstorms seems to have vaporized and they have left no trace. 

Does anyone know where I can get the educational (not home) version of the Classic LEGO Mindstorms development environment for the Mac OS?
It looks like LEGO have indeed completely pulled the previous version.
According to the announcement last year (emphasis added):

Mac Catalina Issues
[…] We have therefore decided to replace the current EV3 Lab software and EV3 Programming App with a completely new app, called LEGO® MINDSTORMS® Education EV3 Classroom. Featuring a coding language based on Scratch, EV3 Classroom will initially launch for macOS in November 2019 and in spring 2020 for iOS, Windows 10, Android and Chrome. EV3 Classroom will offer a consistent experience, features, and content across all devices.

As such, it would appear that this is the only official release you can now download for MacOS from their site.
If you have not yet upgraded your Mac to Catalina, you might be able to use the Mindstorms Lab download from the Retired Products section, where the same warning is included.
If you're unable to locate it on the Retired Products section, a direct link may be available here: LME-EV3_Full-setup_1.4.2_en-US_OSX.dmg