5  Hardly H₂O₃?  (3,4)

10 See 17 Down

11 See 12

12/11       24's struggle with volumes (6,2,3,5)

13 See 4 Down

14 Disdainful 'Hurricane' Higgins, tense, taking on novice (9)

16 Girl hidden in answers? Yes! (4)

17 Friend, if X = 0 (4)

18 Smartest one involved in abuse? (9)

22 Novelist breaking metatarsal in Germany (8)

23 Conductor often seen on holiday (6)

25 Cold quality of nameless river to the east of Scottish water (10)

26 A near-perfect notion? (4)

27 Small fish starts rotting - foul! (7)

28 From Glasgow, say: non-conservative and habitually drunk (7)

 2  Put out search for little green men around South American lake (3,4)

 3  Explorer's termination in arctic boat accident (5)

 4/13        24's advice: do pastoral poems perplex? (1,6,8)

 6  Dramatist's stunning victory supporting revolutionary (6)

 7  Proverbially, it cried cool tears (9)

 8  Endlessly cook hot stuff for dessert (7)

 9  Magistrates sit about and write journals (13)

15/20       24's bird is consuming clergyman over time, dancing with lust, oddly (9,7)

17/10       Totally flipped, however a rival city volunteers 24's work (1,4,2,1,3)

19 3 as cheeky sauce (7)

20 See 15

21 It's a sin, yes? (6)

24 Satirist succeeded with independent newspaper (5)