The unclued lights (as four pairs and a singleton which includes an abbreviation and apostrophe) are of a kind. 36 is an acronym and 10 includes an accent. Solvers should highlight a further themed title of two words hidden separately in the
final grid.
 

Across

1    Sheriff’s officer’s wild spat during argument (8)
12    Land on tree; mother has pronounced dead first (10, two words)
13    English work about wing flap (6)
14    24 change of heart for this bishop (7)
15    Girl in The Crown that’s on her knees (8)
18    Pair paid the bill on both legs? (9, hyphened)
19    Former PM presenter with sound of whirling...