2106: 30/3

30 3 is a definition of one unclued light (which 34 follows) and also a cryptic indication of 16A. 34 is marked by the holder of the 16A with a 40. One unclued light is the name of the 40, and one is the name of the holder of the 16A. One of these lights consists of three words.
 
Across
1 Nippers in scrape, first to last (5)
6 Criminal cases involving youth in attacks (8)
12 Standard answer with humourless face concerning appendage (10)
13 Wiped notice about black and white herons put back (9)
14 Old-fashioned expression of surprise over medal (4)
15 Clutches appeal to stop cheats (8)
17 Web including section for inventor (5)
21 Stones rested in beach back behind tangled net (11)
22 Stems reflective child winds (7)
24 Entranced, not having resistance ready (3)
26 Vessel’s become less tense (3)
29 Deviation by rat on wandering round country (11)
33 Spiritual leader about to contain decline (5)
35 Chaps receiving cheers see crosses (8)
37 Be indisposed to follow new tack? (4)
38 Agent frames fixers (9)
39 Fruit, first in Eden, left race filled with sin (10)
41 Amounts of information via regular round (5)
 
Down
1 Pursuit involving activity lacking right discipline (8)
4 Dry lecturer in charge in form (6)
5 Energetic performer runs monster ragged in court (11)
7 Treat to go north in vehicle on a break (7)
8 Bird weak in advance (5)
9 Part with one in trouble about endorsement (8)
10 Prepared account on habitual responses in art of teaching (8)
11 Instructive system using spades, oddly shuffled, discarding diamonds (5)
16 Force arresting pirate or crooked owner (11)
18 Sure theory essay covers (3)
19 Check on new biro held by composer working at a desk (10)
20 Next to nothing secured by dodgy dealings (9)
23 Send in drinks for followers (8)
25 Judges for instance and saints in spots (8)
27 Constituent of opium not available?  See...