ernestworthing - Go to your home folder, then your Library folder, then the Workflows folder, then the Applications folder within there, then the Finder folder and delete the workflow you don't anymore.
For those who want the simpler path it is: ~/Library/Workflows/Applications/Finder
Silly me... it just occured to me that I could've just created some uniquely named plug-in and searched for it with Spotlight, in order to find out where Automator stashes the plug-in. ;-)