Thanks Adam.
I've found the cause of problems and hence have worked around.
The editor was embedded in an Ajax Update Panel that seemed to cause the problems (a clash of technologies I suppose).
Now the spell checking works and all toolbar icons appear. I'm still concerned by the length of time it initially takes to load the first lot of tool bar icons (it seems there are about 113 odd images to bring down before we are working even when I cut down the number of items in the toolbar).
What I'd like to see is an example of how to use the Editor withing Ajax Update Panels and the best practice approach to setting up a customised Toolbar. I'm sure most of my problems are due to my ignorance.
Thanks. A great product generally and I hate to sound too negative.
Geoff