Thank you Joel and everyone. It was a box, but now it is a C U B E !!! (I like the comments that have been made in the workshop about that.)
Just a bit of background for you, I actually only downloaded and installed Blender this morning, which is what I used to create the object. It's the first ever 3D thing I've done - a bit of a learning curve. The links to the Frontier examples aren't available yet so I had to do a bit of guesswork on what to do to create the required 6 levels of detail. I just duplicated the object so that we had 6 of them with the required suffixes from the user guide.
Because I made 6 of them, I moved them around in the world so that I could see them all, and I think that is what made the cube dance around when zooming in and out. For now I've just put them all back in the same spot, overlapping each-other, and I think that has now fixed it in the revision I've just uploaded to the workshop.
I'm really pleased to have had the opportunity to be the first ... and I'm looking forward to what those with a lot more creative talent than I will achieve with the new system. It seems it will open up almost unlimited opportunities.