Across:
1,16dn. I gee up 2, a pawn transformed into sovereign (state since 1975) (5 3 6)
4. Joked after end of struggle with gear (8)
9. Country with a trust mostly broken by endless renaming (9)
11. Start of dalliance turned disappointing with lack of erection (5)
13. Staff of 25 liners, and what their patrons do reportedly (5)
14. Nosh... a Nashi, as per rewriting? (5 4)
15. Sadly, lads sin in places surrounded by 25 (7)
or  15. see 26
17. Advice to guitar player to stick to single notes, a bitter pill perhaps? (7)
18. Given wealth, but need DOW to go off! (7)
20. Playing part in romantic harm, erect seductive guy (7)
22. Contrived an air, hurt like the Lady of the Lake perhaps? (9)
24. Roast diced or ground vegetables in 1 16 (5)
25. Cone A-shaped, in the main (5)
26. Top brass aid military in mysterious ways... not every one is included (9)
28. Within Cubism, arc known to be influential figure of 19th century Prussia (8)
29. Half of document submitted for largest of the 26 15, in the 28 9 down (5)
Down:
2. Singer from the Torres Strait 15 seen in 29? (3)
3. As for 'fuzzy' hairstyles... (5)
5. Faux quails flying with no line (5)
6. Bring up some praise, nod nicely - they control half of 16 down! (9)
7. Explorer put bridge over one (7)
8. Let's dance... clumsily out of time so no longer dirty (8)
9. Log cheap air travel in spread of 15 (11)
or   9. see 28 across
:10. Contract: she will provide currency to old 16 (5)
12. Half tropical, from south (more south by southeast) city of 1 across 16 (4 7)
16. see 1 across
17. Moniker can be this or variation? (8)
19. Red's hit badly, but fails to act decisively (7)
21. Claim you hear via Signal, finally getting the big picture (5)
23. Is a chartered accountant turning prophet? (5)
24. Low noise beneath ruminant's guts (5)
27. Mostly tight foreign character (3)
Solution:
PAPUA==EQUIPPED|
=N==F=C=U=N=I==|
AUSTRALIA=DROOP|
R=H=O=E=S=O=N=O|
CREWS=ASIANPEAR|
H=L===N===E=E=T|
ISLANDS=NOSTRUM|
P===E=E=I=I===O|
ENDOWED=CHARMER|
L=I=G===K===U=E|
ARTHURIAN=TAROS|
G=H=I=S=A=H=A=B|
OCEAN=ADMIRALTY|
==R=E=A=E=U==A=|
BISMARCK==MANUS|
Name: 868 - Promoted Pawn
Author: by BenDR
Annos-Across:
1,16dn. *(I GEE UP [ANU] A PAWN)
4. (struggl)E + QUIPPED
9. A + *(TRUS(t)) + ALIA(s)
11. D + r(POOR)
13. hp( CRUISE )
14. *(A NA(sh)I AS PER) [ "nosh" = no 'sh' ] &lit
15. *(LADS SIN)
17. NO + STRUM
18. *(NEED DOW)
20. tel (romanti)C + HARM + ER(ect)
22. *(AN AIR HURT)
24. *(ROAST)
25. *(CONE A)
26. *( A(i)D MIL(i)TARY )
28. tel (cu)BISN ARC K(nown)
29. MANUS(cript)
Annos-Down:
2. (m)ANU(s)
3. *(AS FOR)
5. *(QUAI(l)S)
6. rev tel (pr)AISE, NOD NI(cely) <
7. ONE in PIER
8. *(LE(t)'S DANCE)
9. *(LOG CHEAP AIR)
:10. SHE'LL
12. r(TROP(ical)) + MORE S BY
17. *(MONIKER CAN) - *(OR) &lit
19. *(RED'S HIT)
21. tails - (clai)M (yo)U (hea)R (vi)A (signa)L
23. IS S + r(CA)
24. middle of (benea)TH RUM(inant)
27. TAU(t)