This crossword No. 12479 clues and answers were published on Mon 10 May 2010 and the puzzle can be visited by following The Guardian Quick Crossword No. 12479 link.
All Across Clues and Answers:
1-across – Sleepwalking : SOMNAMBULISM
9-across – Grades : RANKS
10-across – Plunder : RANSACK
11-across – Midday : NOON
12-across – More rats : REARMOST
14-across – Ship’s kitchen : GALLEY
15-across – Place of worship : TEMPLE
18-across – Defective : IMPAIRED
20-across – Determined — grim : DOUR
22-across – Labourers : NAVVIES
23-across – Audibly : ALOUD
24-across – Genteel fools : LETONESELFGO
All Down Clues and Answers:
2-down – Self-inflicted loss : OWNGOAL
3-down – Meddlesome : NOSY
4-down – Red Rum : MURDER
5-down – Daunted : UNNERVED
6-down – The Gem State : IDAHO
7-down – Reach the desired standard : MAKETHEGRADE
8-down – Brief sensational play intended to horrify — urging old nag : GRANDGUIGNOL
13-down – Treason — it is done : SEDITION
16-down – Lengthen in duration : PROLONG
17-down – Population survey : CENSUS
19-down – Swivel : PIVOT
21-down – Effrontery : GALL
This crossword has in total 24 where 12 are across and 12 are down.