2597: A couple

Five unclued lights are connected with one partner, four with the other. Another links both.

Across

1    Nervous about yarn being threadbare (6)
11    She intervenes, announcing press deceptions (9)
12    Currency heretic returns (5)
14    Saviour’s foul-up: I take fright, losing head (9)
16    Switch middle of tracks for competitions (6)
21    ‘Estimates’ (6)
22    Joins college team with backing (6)
24    New serum transformed little Oz birds (3,5)
26    Track aircraft losing pressure (4)
27    Detailed plan for fish (3)
28    NZ native a little like Australian (3)
29    Some Nigerians find one chief a bit off (4)
32    Not free to resort to special water additive (8)
34    Wit has energy to spar (6)
35    Killing some way out to sea (6)
40    Fellow took sick and died (6)
42    Pill taken, horrible, as something green (9)
43    Cut up small parasites (5)
44    Band member, perhaps star I twice smashed in stomach (9)

Down

1    Such dirty talk turns stomachs (4)
3    Clerical tasks get Mike in a row (5)
4    One that writes book, nothing in pencil? (4,3)
5    Grooms collecting film for kids (8)
6    Win confidence of detectives’ branch (6)
8    One is dark, heartless (4)
10    Section of abdomen, you correctly say (5)
13    Inflammation non-U 44s suffer (9)
15    Plastic box collection held by hereditary class (8)
18    Annual price so-so, fluctuating (9)
19    Marxist entertainment doesn’t answer to publisher (4,4)
25    Raised obese and weak, getting stern protection (8)
26    Hooligan in riot half interrupting poet (8)
30    Spear US bum one more time shortly (7)
31    Bridge tactic from almost the best two players (7)
33    In plant, half of speech I sound hesitant to follow (6)
38    Left in agony, it’s obvious (5)
39    Giant electronic web falls over (4)
41    Decaying and dying old trees, yews principally (4)

Download a printable version here.

A first prize of £30 and two runners-up prizes of £20 for the first correct solutions opened on 10 April.