Upon inserting a footnote in a libre oo document, the paragraph spacing goes a little haywire above the footnote. ie. the footnote number is too high or the spacing ‘buffer’ around it is too much.
I’ve played with the settings for footnotes whilst the footnote is highlighted in format>character>position
…But no luck yet! I’ve included an image of the problem and the footnote settings (these are when the footnote is highlighted).
(Edit: activated screenshots)
Direct formatting, i.e. manual formatting with menus and buttons, has no effect on footnote anchor. To change note anchor appearance, you must modify Footnote Anchor character style. This is so because notes involve specific processing and Writer internally takes control. What LO Writer does can be tuned through specific character styles which names are defined in Tools>Footnotes/Endnotes.
Press F11 to show the style navigator
Click on the second icon from the left in the tool bar (Character Styles)
Right-click on Footnote Anchor and choose Modify
Modify to your liking
If this answer helped you, please accept it by clicking the check mark 
to the left and, karma permitting, upvote it. If this resolves your problem, close the question, that will help other people with the same question.
This worked a treat, thanks very much (karma does not permit upvote sorry!).