The unclued lights (one of two words) are of a kind.

Across

1 Bringing down plane that was used on D-Day (7,5)

12 Heart tremor? (10)

14 Member in bar, musing (3)

17 Folds in damask curtains partly drawn back (5)

18 Married? Possibly him! (7)

19 Provide plaster (6)

22 Agamemnon’s father sure to be murdered after a time (6)

24 Entrance halls where amateur contest gets cut (5)

26 Having just one connection travelling via tunnel (9)

29 Biblical heroine abandoned by husband in compound (5)

31 Tenor dear to the Italians around the States (6)

34...