How to download Mojave from a Catalina desktop?

Hi everyone, I’m having a play with MacOS on my UnRaid server as a VM. At the moment my only Mac is a spare 12" MacBook running the current dev beta of Catalina.

I’m trying to source the Mojave installer from Apple rather than…elsewhere… such as dosdude’s patcher.

If I search in the App Store it returns nothing. If I search in Google and then follow the links from the App Store web page to Mojave, it takes me to the OS in the App Store and I can successfully start to download it. But it kicks off the download via Software Update in System Preferences. When the download completes I can’t find the installer and it errors about compatibility, I assume because it wants to open and start installing on a newer OS.

Does anyone know where the downloaded OS would have been cached locally so I can grab it and move it off onto my network storage? Failing that does anyone know how I can download Mojave successfully from Catalina?

Thanks!

Catalina doesn’t store the downloaded Mojave installer in /Applications like many recent versions of macOS?

Nope. I managed to get it but not via official avenues.