Clockwise round the grid run six of a kind (one of three words and one three-word pair). Other unclued lights show where you might find others of their kind. Unchecked corner letters could give PLAY-DEN PLANK.
 

Across

11    With everyone away, call hourly for singers (6)
13    Old bird biting end off confectionery (3)
16    Group of people, just the first section (5)
17    Left in the rain, following ordinary bird (5)
18    Power to clear out stretch of land (6)
19    Joke about family breaking up (6)
20    Develop strong emotion, turning against English (6)
21    Bills from old masters (5)
22    New mentor works in vacation (7, hyphened)
28    Commanded to capture American ship, one enemy of theirs? (7)
30    Ferment as poet switches ending (5)
31    Master cast medieval helmets (6)
34    Philosopher shortly holds answer for statesman (6)
36    Tree bark covering poorly (6)
37    Help no more in contested election (5)
38    Very keen on drinking beer, finally opening bars (5)
39    In hearing, fail to notice singular couple (4)
40    A side petal regrettably pruned (3)
41    Welsh town lacks principal two pieces of pasta (6)
 

Down

2    Penguin medley (8)
3    Resolve to change Teddy (9)
4    Woman almost fit to be scarecrow (6)
5    Given the word, men run into action (7)
7    Pirandello’s resistance for one unknown disease (5)
9    Lisa’s predecessor takes care of state (6)
12    Ted leaves airport, crossing a thousand ditches (6)
21    Baton said to be wielded as punishment (9)
23    After setback, stupidly erase passwords (8)
25    Black belted in martial art, I do drop out, turning up for sausage (8)
26    Wine, one picked in dispute, say (6)
27    Is not even able to eat here (7)
29    Handsome man’s election splits Greek extremists (6)
33    Art school pop group (5)
35    Still in bed? Pretended to have risen (5, two words)
 
A first prize of £30 for the first correct solution opened on 18 September. 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 2325, The Spectator, 22 Old Queen Street, London SW1H 9HP. Please allow six weeks for prize delivery.