chrisw
See this file -
it contains all the text from your file I downloaded but has no formatting.
I got all the text out by:
1 Extract \word\document.xml by un-ZIPping the .docx file
2 Open document.xml with
Notepad++3 Go Search > Replace ..., with search argument <[^>]+> and replace argument is blank. Be sure to tick Regular Expressions. Click Replace All.
This removes all the XML tags and leaves just the text.

- Notepad++ Search using Replace to remove all XML tags
You cannot do this in Writer because the XML contains more than 64k (actually 65,536) characters all in one single paragraph. You can paste the entire XML into Writer but as soon as you then try to do anything, Writer crashes because you have exceeded the Writer 64k paragraph limit. If you want to use Writer you need to split document.xml into parts where each part has less than 64k characters.