3  Faint security measure? (5,3)

 8  A B C D F or G? (4)

 9  A city obsession - the possibilities are boundless (8)

11 Thinking quietly about one's image (10)

14 Sadly inept, I use this when dressing formally (3,3)

15 Maroon thread (6)

17 Seeking perfection, I meet crazy ladies with nervous twitch (10)

20 Visibly upset, I get data processed (8)

21 Ascetic resident of Jellystone (4)

22 Pull up suddenly, unhappy about wrecked depot (4,4)

23 Unknown churchman loses his head (4)

 1  Building a minster’s towers (8)

 2  Gave formal consent to India after I'd gone mad (8)

 4  Dimension leading explorers never get to handle at the start (6)

 5  Thread to follow Peter's sister (10)

 6  Poet's overdose around six (4)

 7  Strung as evenly, they provide marine power (4)

10 Late, as a polite cough may be (10)

12 Depressed actors finish off their drinks (4,4)

13 Drawing out non-adult training (8)

16 Arrived before artist could be shot with this (6)

18 Obstructs watering holes (4)

19 Artist is some rising minor impressionist (4)