Solving time, 14 mins
* = anagram
ACROSS
1 CUB A
3 DE-CREED
8 ARABIAN NIGHTS (aghast in NI bar)*
9 A RR (Right Reverend) ESTEE(m)
10 FUR ROW
11 INLIER I in (liner)*
12 SCOT-FREE (Secret of)*
14 STAG N ATE
17 S TRE (A) K
19 BUS T-UP
21 PLA CABLE (pal)*
22 FINANCIAL YEAR As Government spends as well as taxes, I think
23 E (A ST) END (need)*
24 STEN Hidden in previous answer
DOWN
1 CHA GRIN
2 BE (AVER) ING
3 D ANGERS
4 CHIEF CONSTABLE (catches big felon)* less g
5 ETHER (Well) hidden
6 D (IS P) OSE
7 VICTORIA SPONGE (a top covering is)*
13 FIRM (AMEN) T Good surface
15 T RUFFLE
16 E MP TI(r)ED
18 AILERON (one liar)* aviation
20 (in) TENDS