Thx very muchly for all the comments. I knew there would be an explanation. I did know about the widows/orphans - read here on this site I think. I set mine also to "0" and it's added as a conversion via calibre.
I rarely have a problem now, but I still see an occasional strange space, or single line on the next page.
Not sure I want to play with the firmware to get it better. I can live with it. Maybe Kobo will rectify it one day - but then again, I've seen more flying pigs!
I exclusively use epubs and am slowly getting to grips with sigil. I'll never be an expert
I really wasn't prepared for how inconsistent ebooks are when I brought my Kobo
Thx again for the help.