2350: Pieces

The unclued lights, (two of two words), individually or as a pair, are of a kind and can be resolved into three separate trios. Ignore all accents and apostrophes throughout the puzzle. The highlighted squares, read in order row by row, reveal the sources of the trios.
 

Across

7/8   The whole capital of Hainaut gets call to court (7)
13    Topical review that’s mine (7)
15    Mountaineering peg without a pointed end, on reflection (5)
16    Town in Fife giving trophy to Albion Rovers initially (5)
17    Torn shred from lace worker, it seems (6)
20    One mooring a boat reportedly in capital (6)
22    I am interned in stable, treated like an animal (7)
27    Discharge from former Minoan location (7)
29    Goldfinches in a group delight (5)
30    Greeting Welsh saint of old (6)
32    Special edition appearing in crowd scene (5)
34    Hanger-on’s legal right in court (6)
36    Bone from ancient city (5)
37    Boat clubs right at the back (5)
38    Brighter fish. That is right (7)
40    Regular antics of friendly goblin (3)
41    Breakfast grain, maybe, from Lee’s bedside (11, two words)
 

Down

1    Returning rearwards in close sequence (10, two hyphens)
2    One bitter fool at press agency (8, hyphened)
3    An impulse cultivating spleenwort (9)
4    Accidental and wonderful sleight of hand (12, two words)
5    Wild cats left out in capital (7)
6    Nobleman mixing meringues without topping (8)
7    Students’ demo is wrong about sex (5, hyphened)
8    See 7 Across
10    Commercial ships aloft oddly (5)
12    Kill mother’s internet identity (6)
14    Evergreen shrub affected regular pulse (12, two words)
19    Exciting experiences coming — sure to be special (10)
26    Inner chambers where the French friend tossed hat first (7)
28    Sensitive offer for carer? (6)
31    Playwright and wit cut gnu in half (5)
33    Cross beams? (5, hyphened)
35    East European art swindler’s confession (4)
 
A first prize of £30 for the first correct solution opened on 2 April.