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. returning (4)
20    Rating the French as clever (4)
22    Society girl, maybe Lily (6)
24    Land one’s entered before (4)
25    Nuts acting as war entertainers (4)
26    Base rate cut changes level (7)
29    Stylish earl with the glove abroad (7)
31    Ex-county star’s back (4)
32    Sri Lankan loses male dog (4)
35    This party game (6)
39    Lout turns over beatnik (4)
40    Ruler’s verse rejected (4)
41    Resin in time left over (5)
43    Record love — go for long poem (6)
46    Soil some smuggle in (4)
47    Use up energy, a shade old (7, two words)
48    Readily saving soft wood (5)
49    Having teeth tainted, with no cracks (9)
 

Down

2    Small animal’s spawn (4)
3    Decrease team for Edmund (8)
4    One lad’s high without joints? (6)
5    Polish saving river feature (7, two words)
6    On radio, drop harmony (4)
7    Born journalists required (6)
8    Zero money for college (5)
9    Servant less clothed, we hear (6)
10    Way to crack 2×1 for German scientist (8)
12    Making sterile painting right away (7)
16    Oddly glum detainees here? (6)
21    Letter covering unhappy writer (6, two words)
25    Ends mere sex romps? About time (8)
27    A tyrant advanced anonymous works (8)
28    Not so short nap? That’s most curious (7)
33    A PM’s about, not alert (6)
34    Sash on soldiers who use charms (6, hyphened)
36    Scot’s fled loch, one up for moving (6)
38    Rent’s part free (5, two words)
44    Swan on one coin (4)
 
A first prize of £30 for the first correct solution opened on 5 June. There are two runners-up prizes of £20. (UK solvers can choose to receive the latest edition of the Chambers dictionary instead of cash — ring the word ‘dictionary’.) Entries to: Crossword 2310, The Spectator, 22 Old Queen Street, London SW1H 9HP. Please allow six weeks for prize delivery.