The unclued lights (six of two words and one of three words), one pair or individually, are of a kind, verifiable in Brewer. Ignore one apostrophe.

        Across

   1    Declare nothing will stop crime, causing disgust (8)

   6    Attack, losing head in drinking bout (6)

11    Objects to intellects (5)

13    Young girl by supermarket, getting potato (7)

14    Humble faculty head embraces Doc (6)

16    Tail, small and trim (4)

17    Certainly not Greenland! (2-2,4)

21    African, say, on the wing, no good performing (3-5)

23    What about painting crosswise? (7)

25    Half a pound at Greek isle (3)

26    Sea loch oddly not in Seville (3)

28    Fringe...