2372: Spot-on

One unclued light (three words) is a phrase referring to an item whose scientific name is formed by two unclued lights. The first word of this name can be divided into three words, each of which has two synonyms among the other unclued lights.
 

Across

1 Strip back stagecoach seat, not wide (5)

9 Check railway damage in station, causing weeping (10)

11 Artist reversed whole process (5)

14 Second-class designation sadly for red mineral (5)

15 Work in group with no time for sleep (5)

16 Jerks shout to encourage hounds (6)

21 Obtain picture showing slipper (8)

22 Support holding clamped valve (7)

24 Bore wanting new network (4)

27 System of rules broken by youth in branch (7)

28 Allurement in good account penned by visionary (8)

35 Mean, alone, abandoned by son (5)

37 Clear case about part of personality (7)

38 Know almost nothing about chaos (5)

40 Bungling raid, lie to leader? (9)

41 Change direction with tilt (5)

Down

 
1 Out with maiden wearing a ribbon? Indeed (13, three words)

2 Pasture we also modified (6)

5 Radical in revolutionary league (4)

6 Crime admitted by a dupe? That’s funny (7)

7 Work about rising above grade (5)

8 Opened out strange old rule about knight (8)

10 Interpreting clue, a mere hint, wrongly (13)

13 Sales promotion stopped by trade union in effect (7)

15 Governor brooded over strike (6)

17 Coined money, various pieces (6)

18 Standard sheet in set (6)

20 Devotion losing power after second half (6)

23 Serious in purpose, impressed deeply (8)

26 Coach opening up about music (7)

29 Fallen angel criminally liable (6)

30 Place secured by band in display (6)

31 Wood entered by ordinary track (6)

32 Rumour in second item (5, hyphened)

36 Fibre in bread (4)

A first prize of £30 for the first correct solution opened on 3 September. There are two runners-up prizes of £20.