Miracle of miracles scshrugged...EasyFind helped me to find it! Even though it found it in the /Scrivener/Backups directory when I looked there from within Scrivener the folder was empty. inexplicable...thanks everybody...i need a drink...it's 5 o'clock somewhere
For future reference, it is completely explicable that the backup files were not visible from within Scrivener: they are ZIP files, and Scrivener can only open .scriv files. To open a backup, you need to uncompress it in Finder, then open it.
Happy to hear you've recovered your work.