Unclued lights (including one pair giving a name, and one of three words from a quotation) form three groups; the word that links them all must be highlighted in the grid.

        Across

   1    Make bourgeois rogue grin, yet to embrace female (8)

   8    Small cover for head or neck (4)

11    A sailor pockets peso with original value (2,3)

14    Old Yemeni’s brief month in Israel (5)

15    Some poetry’s mood extremely humane (7)

17    Expert delaying old emperor (4)

18    Politician blocks great excuse (5)

19    A relative pens book having no life (7)

23    Fish in benign border of greenery (4,4)

24    Shearwater bird eats silver...