@Dan ODonovan You can manually remove a workflow by right-clicking it in the sidebar, revealing it in Finder and deleting it there.
Google Drive isn't a suitable sync service for Alfred's preferences, so you may find you encounter other issues, such as your preferences not being available on startup, resulting in Alfred creating new preferences, or conflict resolution being rather poor if you've changed files on two Macs at the same time. I would encourage you to back up to Time Machine regularly if you choose to use GD to sync your preferences.
