One unclued light is the origin of the remaining unclued lights (three of two words), individually or as a pair.
 

Across

4    Stagnation’s the making of these adversaries (11)
11    It’s for refreshment in moderation — there’s no din (7)
12    Reptile from southern-most headland (6)
13    Nut lovers’ collection in Laurel’s birthplace (9)
14    King of England swapping old money in 37 (5)
16    Motionless, it can make the spirits appear (5)
19    Child beginning to trust stranger gets left imprisoned (7)
21    Note time on Orkney isle (4)
23    Sin from Bible — a run on diamonds (7)
24    Smile and phone, when cycling (4)
25    Corrupt police? Constable’s work they might enhance (7)
30    Fighting en masse? You need protection (7)
31    Very dark, like Fort Knox (4)
34    Crusts of Native-American bread (4)
35    Internet idea not corrupted as souvenir (7)
37    Put choral finale in Passion? It’s over to composer (5)
40    Wool supplier group of shops rejected (5)
42    Monstrous dame in city’s ancient native quarter (6)
43    Besides having tea outside in London (7)
44    He’s with it, and others will be later (11)
 

Down

1    Fit, lusty drunk with gin cocktail but dull (11)
5    Norse fate providing Hobson’s choice of letters (4)
6    Headless ghost wandering? Nonsense! (4)
7    Good chance it is where to start taking a breather? (7)
10    Cut short attempt to be of help to Labour (7)
15    Fanny for president? (5)
17    Contain popular hint about Doc’s introduction (7)
20    Wild West marshal having to carry bung (7)
26    Title-holder’s depressing experience, losing head (5)
27    One who helps in centre for inalienable rights (7)
29    Biofuel found in fuel filling station (7)
33    More than one bar keeps back Poles (6)
36    In the Big Apple, nothing is turbulent (5)
38    Club accepts hard currency (4)
39    King, born a woman, may have been bent (4)
 
A first prize of £30 for the first correct solution opened on 20 March. 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 2299, The Spectator, 22 Old Queen Street, London SW1H 9HP. Please allow six weeks for prize delivery.