@theboyuk - OK figured out that Adobe docs, with regards to Mac, are slighlty vague. The reason I was getting "AdobeUpdateServerSetupTool: command not found" is because of the command itself.
If you're running the command from the location of AdobeUpdateServerSetupTool, instead of:
AdobeUpdateServerSetupTool --root="/serverroot/updates/Adobe/CS" --fresh
Run:
./AdobeUpdateServerSetupTool --root="/serverroot/updates/Adobe/CS" --fresh