That was the problem, the dialog box wouldn't appear. So, I couldn't make these changes. Everthing was at the command line only.
I did a reboot then a 'repair installation' and it now works fine.
I believe my workstation is falling appart little by little and will need a total format, etc... at some point. Of course, I will put this off for as long as I can.
Thanks anyway.
craigr