How to activate an Automator application with AppleScript?
I was being stupid. This version works:

tell application "Finder"
    try
        open "Macintosh HD:Users:TheUser:Desktop⁩⁩:Automator test 2"
    on error
        display dialog "could not open the automator"
    end try
end tell


Just have to use the tell finder command and open instead of open application.