There was an easier way, but I'm not sure if you want to know it now you've just done it the hard way
Here goes anyway (for future reference)...
1) go to versiontracker.com
2) download and install pacifist
3) insert installation discs and follow pacifist instructions
4) locate the utilities on the disc and copy back to applications folder
5) Finished.
Works with any part of the default system accidentally deleted too...