Unclued lights are six characters from 45 and its author. Five of these undergo 45 in one way before entry; the other two must undergo 45 in another way afterwards (leaving real words). Collins confirms the thematic information.
 

Across

1    Radical dissent about America’s dirty quality (9)
11    Briefly desiring drug (7)
13    Endlessly long time (4)
14    Apennines loop around from peninsula (13)
15    Loathing crone keeping money (6)
17    Tradesmen are not seen in half a millennium (5)
18    Bird from north, e.g.