2641: Mastermind

Two of the unclued entries combine to form a name (three words) responsible for the other unclued entries (one of three words, two of two words, and two of which combine to form a two-word name).

Across

11    Custom I outlaw, hiding books for islander (7)

12    They must cool down the crowd (4)

14    Cast spell over snake in Paradise Lost? (6)

15    Natal piece, that is ejected somehow (8)

17    Fruit is cut back (5)

19    Things a man hates terribly (9)

21    The wrong tribe ultimately settled in Nevada desert (5)

23    I was a boss and had nothing to do (5)

25    Songbird’s attempt to conceal guano in retreat (8)

26    Laurel’s base said to be in ME capital (6)

27    Composed Home Counties girlfriend (6)

31    Hal backed out of ME capital with branches (5)

33    I prepare the ground in soft state (5)

34    Using French, I trade in odd ME capital (9)

36    Secretive type keeps nothing in pots locally (5)

39    Former province getting island city out of nothing (2,6)

40    Angler’s fly to cast reel (6)

41    Care about ruined person losing weight (4)

42    Coped with a name? (7)

43    Plagiariser caught cheating in deserted stock? (4-8)

Down

2    Someone inclined to accept loan for one finishing paper (9)

3    Olivia’s excited to eat cold chicken (7)

4    One’s waiting for these dumps? (4)

5    Artist went fast and was grating (6)

6    A bull violently breaking fancy vase and other such items? (9)

7    One governed ME country (4)

8    Forebears like central impressions (10)

9    President (America) backed sacking a governor (7) 

10    Pay to play in Brazilian team (4)

16    Most read novel ranged around the countryside (8)

18    Solar area penetrating like a screw (8)

20    Informed sailor having style of management by 7 (10)

22    Destroyed all morale with certain projections (9)

24    Local clothes shops dug into passes (9)

30    Currency protects city that can be governed (7)

32    City dam almost clear of water (6)

35    Cut length for...