1. Only sort of aspiring to the latest style? (5,1,7)
AFTER A FASHION - double definition.
8. I’d knocked over stringed instrument, showing reduced concentration (6)
DILUTE - I’d knocked over (DI), stringed instrument (LUTE).
9. Hostility in US Institute in Eastern US city (6)
ENMITY - US Institute (MIT - turns out to be the Massachusetts Institute of Technology which does seem a rather odd piece of GK for a QC) inside eastern (E) and US city (NY).
10. One that’s invested in munitions (4)
UNIT - inside the clue - m(UNIT)ions.
11. Speed after crashing? Most of story provides support for figure (8)
PEDESTAL - anagram (after crashing) of SPEED, most of story (TAL)e.
12. Material presented includes opening of clever comic play (5)
FARCE - material presented (FARE - food served at a restauarant), including (C)lever.
13. Hurried to consume last of sweet cake (5)
TORTE - hurried (TORE) to consume swee(T).
15. Wild party? Cold awakening (8)
CAROUSAL - cold (C), awakening (AROUSAL).
17. Wrong description of second-in-command? (4)
VICE - double definition.
19. Component of avenue, say, is seen in stone road (6)
STREET - component of avenue (TREE) inside stone (ST.
20. Immediately aware of following publicity experts (6)
PRONTO - not presto - aware of (ONTO) following publicity experts (PR).
21. What might nevertheless be made up of thin sunshine? (5,8)
BROAD DAYLIGHT - cryptic definition - which I liked enough to make a contender for COD.
2. Pretend female will get time in power after deposing Queen (5)
FEIGN - not feint - female (F), time in power r(EIGN) after deposing Queen (R).
3. Circular line converted to square (but not initially) (7)
EQUATOR - anagram (converted) of (TO) s(QUARE) - but not initially . Another COD contender.
4. Pain yielding hearts — it’s a high card (3)
ACE - pain (AC)h(E) yielding/giving up hearts (H).
5. Dance a lot, jiving, according to the stories (9)
ANECDOTAL - anagram (jiving) of DANCE A LOT.
6. Decomposing material smells badly around University (5)
HUMUS - smells badly (HUMS) around University (U). Didn’t we have this clue recently? Copied from Roly's blog last Thursday - 10. Decomposing matter emits awful smell around university (5)
7. Dismissed start of Roman era in fury (7)
OUTRAGE - dismissed (OUT), (R)oman, era (AGE).
11. What will pin down a Romeo among the reporters? (5-4)
PRESS-STUD - Romeo (STUD), reporters (PRESS) so a Romeo among/who is a reporter is a press-stud.
12. Praise insincerely, showing less depth (7)
FLATTER - double definition.
14. Start of recipe with garlic mayo encompassing very Italian dish (7)
RAVIOLI - (R)ecipe, garlic mayo (AIOLI) containing very (V).
16. Last character is nothing very big (5)
OMEGA - nothing (O), very big (MEGA).
18. Contract snag? (5)
CATCH - COD - straight definition of contract snag (a snag/problem in a contract) = catch, contract (an illness) = catch, snag (on something) = catch. So what is this? A triple definition or a double definition parsing?
20. Wages: penny a year (3)
PAY - penny (P), a (A), year (Y).