It appears I may have jumped the gun here. So far this only happenening
to a single file and it happens whether I save the file
programmatically or manually. Almost as though the workbook has been
corrupted by the PC that created it (somewhere in Europe).

A wierd form of corruption though, and I'd still like to hear from
anyone with any insight on this. It may yet turn out to be a
show-stopper.

NickH