Writer index running over two lines

I have carefully marked a large number of court cases in a document I have prepared so I can have an index of the cases and a reference to the pagers where they appear. However when I seek to create an index I get after each entry a series of colons and also two lines of dots come before the page number appears as set out below. This means that that each entry in the index runs to two lines rather than one. Any advice please on what I am doing wrong either in the creation of the index subjects or in the creation of the index itself. I am using version 7 of LibreOffice.

Abingdon Corporation v James [1940] Ch 287: : : : : : : : : : : : :…
… 60

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