Try http://macromates.com/wiki/Troubleshooting/RevertToDefaultBundles
Thank you. I checked out the repository and removed my 'Pristine Copies', but the new Shell Script bundle didn't show up until I deleted UnixShell inside my own Bundles directory. I have to say that I find Bundle management a little hard to understand - but I guess most TM users are more geeky than me.
:-)
-- Bruno