"Jiggery-Pokery" by Araucaria

The theme is BRIDGE: JIGGER is a bridge at billiards; POKER, like bridge, a card game. Variations: 1 - literal Bridges: (a) in London (b) abroad (c) translated; 2 - river with famous Bridge; 3 - charge for Bridge; 4 - Bridges "of"; 5 - Bridge = supporting structure; 6 - Bridge = card game.

9 See 21 down
10 IS/ADO/RA
11 T/ALL/AHAS/SEE
12,24 L/ON/DON
13 S/ANDERS/ON
15 ASSES (pl. of AS) (Pons asinorum)
17 A/V-(s)IGN/ON(e)
18 VECCHIO (anag)
21 SIGHS (size)
23 A/L/L END/S U/P
24 See 12
26 BLACKFRIARS (flak briers)
28 EASIEST (hidden)
29 AUC/TION

1 WHITE SEA
2 PRO/LONGING
3 SOYA BEAN (anag)
4 ARE/A
5 FIRST NOVEL
6 CAM/ERA
7 TO/LL
8 BA<R>NES
14 SAN/TA MAR/TA
16 S/CH<IS/MAT>IC
19 CONTRACT
20 OP/POSING
21,9 SYDNEY HARBOUR (anag)
22 SU<BL>ET
25 NOSE (Roman, high-bridged)
11 KWAI (cry/cwy)