Hello Beowulf,
0.27 didn't work with different options and/or pages. Fell back on 0.26 and worked fine. Returned to 0.27, restarted and nothing

. I have just tried 0.28 and works perfect.
Got me disoriented because the console window does not appear any more. Thought it was not working. Then Calibre opened and there it was.
Cool cool cool.