The unclued lights (one hyphened and plural, and another in the past tense) are of a kind, all verifiable as such in Chambers, most of them on a specific page.

        Across

   1    One son half-naked, at first, during old broadcast (12)

10    Bird losing head and part of foot (4)

12    Series of files from Game on BBC once (10)

14    Return of low relative from abroad (3)

17    Fruit found when Christmas in over, Frenchman penned (5)

26    Find fault with husband and unnamed folk’s cellular radios (3,6)

27    Bess and Isaac worked out geometrical co-ordinates (9)

29    Craftsman for two generations (5)

31    Stage of journey in...