I found this very easy, solving time 11 mins.
* = anagram < = reversed
ACROSS
4 FIRE D RILL
7 DEL(p)HI Definition/wordplay splits at capital/city
9 RE(A)CTOR
10 NOT HALF
11 SEE KING
13 A RR EARS
14 THEATRE-GOER (the great ‘ero)* & lit. I guess Quixote went for the full anagram to give the &lit clue. But the three parts lie side by side, with ‘the’ unaltered. Nothing wrong with it, needless to say.
18 ER (RAT) IC
20 T (SARI) NA ant<
21 FIDEL Castro I O Opera by Beethoven, think it might have featured in the 2009 Proms.
22 S WIN D LE
23 RU ST(a)Y
24 SP (LEN DO) UR
DOWN
1 ARBALEST (a blaster)* Old crossbow.
2 BI (TT) ER
3 A L (PACk) A
4 FOR EST
5 DETRI (tired)* MENTALLY
6 LINEAMENT (men in tale)*
7 DETER I ORATION
8 IN FE(a)ST
12 GET A CROSS
15 RA IN DROP
16 REEFER Double definition
17 CAR E’ER
19 R A DISH
22 S ALE