[Update:]
As soon as I'd submitted my reply I had another thought.
By taking the .TXT file and manually editing it to replace the first space of every line with leading spaces into a dot e.g.
Code:
This is my dialogue
becomes
. This is my dialogue
I was then able to get the TXT conversion with 'Preserve spaces' to work.
i.e convert TXT to EPUB/MOBI with:
- Convert - TXT Input - 'Preserve spaces' checked
- Convert - TXT Input - 'Treat each line as a paragraph' checked
- Convert - Look&Feel - 'ExtraCSS' set to p {font-family:monospace; font-weight:bold; margin:0;}
My resulting EPUB doesn't look too bad - despite the dots. see below