7  Say nothing - the doctor's an idiot (4)

 9  See 5

10 Barney enters chorus, being a cheat (8)

11/17       Old DJ but, in part, deliverer of 42 (4,7)

13/25       Hot houses badly hurt recipient of 42 (6,4)

15 We will admit ring is returned by accident (8)

16 Some clothing's colour turned water filthy? (8)

18 Symbol of nationality some citizens ignore (6)

20 Travel around Australian island (4)

21 A thing turns into something stiff here? (8)

24 Strange agility, ranting as a flatterer (14)

25 See 13

26 See 5

 2  Old man revolted by his lice (5)

 3  Japanese drama accepting sci-fi writer's help (7)

 4  Given steel cross, church opens after check (10)

 5/9/26           42 6 17 friendly interviewer hasn't even cracked (3,6,2,4,3,8,3,10)

 6  Leisure centre for sizeable area of Kent (4)

 7  Weather's wrong for wash (5,2)

 8  Troublesome modern studio in China (9)

12 Modest about present/past Internet service, clearly (10)

14 Get wild with old Frenchman in lift (9)

17 See 11

19 Stay firm (7)

22 His appeal is part singing, part songwriting, part body language (5)

23 Stare at good mirror (4)