Import fails

Thanks very much - all about 'knowing where to put the screwdriver' I guess.
Needless to say we'd tried redoing the import many, many times, so it can't just be that. Just to be clear, because it looks like this may happen again ... 'going into the file' just opening the file in Vim/whatever, or opening to edit via WP Dash - are you saying that would be enough to render the next attempt successful?

Since this didn't make much sense (opening the file shouldn't do anything, really), and you're on a Litespeed server, I assume it was server caching causing the issue.

If it happens again, try to disable that server caching completely, then try again. If I had to guess, it would be that :)