@LeroyG: thanks for your help. on LO 7.0.0 (x86) on Linux, Format > Paragraph has no “Asian Layout” tab and no “Write in double-line” check box. This formatting option is completely absent from GUI. Per my comment in response to @ajlittoz’ answer, "Asian Layout and said checkbox do appear pressing F11, and right clicking on : “Default Paragraph style” > “Footnote” …
I’m glad it’s solved.