This crossword No. 21756 clues and answers were published on Tue 30 Nov 1999 and the puzzle can be visited by following The Guardian Cryptic Crossword No. 21756 link.
All Across Clues and Answers:
4-across – A daily glass : MIRROR
6-across – Serpent’s head creates stir – it’s horned! : CERASTES
9-across – Back seat? : SADDLE
10-across – Diplomatic move relates to frontier river crossing : DEMARCHE
11-across – Fail to shear off with cutting blade : PLOUGHSHARE
15-across – One cracked shell : NUTCASE
17-across – Just off Land’s End? : INSHORE
18-across – Inset phrase, maybe : PARENTHESIS
22-across – One was revolutionary and with clear designs : CALENDAR
23-across – Funny : MURMUR
24-across – Needs rig-out bearing trendy label : DESIGNER
25-across – Fellow-traveller back with booze : PERNOD
All Down Clues and Answers:
1-down – Curved member made of wood, say : BOWLEG
2-down – Opening a book : REVELATION
3-down – Mare’s nobbled – poor horse included in runners : MANAGERS
4-down – Dissipated girl in confinement : MISSPENT
5-down – Bloody films featuring old soldiers : REDCOATS
7-down – Instant credit : TICK
8-down – Rose’s mainstay is staunch : STEM
12-down – Cuckoo … wheatears … rook … petrel … : SHEARWATER
13-down – He’s taken aback – by centaur? : HORSEMAN
14-down – Having free time, perhaps idle about? Yup! : LEISURED
16-down – Perk up, dad – face life’s later years! : APPANAGE
19-down – Expression of surprise over habits seen in eg priories : HOUSES
20-down – Missile fleet : SCUD
21-down – Extra-rich husband’s taken off : PLUS
This crossword has in total 26 where 12 are across and 14 are down.