I'm trying to use a link cable to my PC for HereSphere, but after purchasing the app in App Lab, it isn't showing up for download in the Oculus app, any idea what I'm doing wrong here?

App Lab is only for Quest standalone, not PC. You'll need to purchase the Steam PC version of HereSphere if you want to use it on your PC, because HereSphere requires SteamVR to work. There isn't a cross buy option, since they're intended for different platforms.

I refunded the App Lab one and got it working from steamVR, thanks!