Thaks Michael.
1. I am really concerned at this "different level" thing you suggest. I can not imagine how I would have done that.
2. Not that I got the exact close up view as you, I did find things to adjust. Not happy at the whole exercise that these are not highlighted--as per previous discussion, though.
3. I previously had all those areas quite satisfactorily joined, maybe back in the save before that file I sent.
However, here again, I seem to have very satisfactory joins made of all the offending sections, but, now, see how the file opens in Carrara?

Very odd and frustrating. Sorry to have to ask all these questions.
Brian