Best for Puzzles

"Jiggery-Pokery" by Araucaria

The title of the (quite straightforward) puzzle is a far-fetched clue to the theme, which does not itself appear; various variations of the theme have clues (marked V1, etc) which may lack definition.

Crossword by Araucaria

9See 21 Down
10Duncan is trouble (the Sun) (7)
11V1b: Incredible expressions of satisfaction have vision (11)
12/24V1a: Left setting for Rostov (3,3)
13Pooh (they smooth things over) gets on with Tessa (9)
15V4: Roman coins test novices (5)
17V1b: Seconds away from a V-sign (a short one) (7)
18V1c: Old Vic with no echo finder (7)
21V4: Magnitude reported (5)
23Loan most of sum in a record, comprehensively (3,4,2)
24See 12
26V1a: Spooner's criticism that attacks roses (11)
28Requiring minimal effort in case a siesta is taken (7)
29V6: Roman dating must change, not I (7)

1What should be blue or green seems to be covered with snow (5,3)
2Expert with desire for drawing out (10)
3Source of food that makes a boy sane (4,4)
4Live article and (roughly) where (4)
5Completely new work - Golden Ass? Don Quixote? Tom Jones? (5,5)
6Early part of Cambrian period requires secrecy (6)
7V3: Ring given to students (4)
8V1a: Right among causes of wrong (6)
14Health centre on West Country river gets half a tank of Colombian port (5,5)
16Making a breach is lacklustre in Southern fashion (10)
19V6: Lessen (8)
20Piece sitting on the other side (8)
21/9V1b: Management of yore, husbandry (6,7)
22Fat, about a pound, rising, released, as it were (6)
25V5: High, for Roman: investigate (4)
27V2: Wiver makes weporter shed tears (4)