Across:
1. Celebrity turned hack with traitors (7)
5. see 13
9. Revolutionary stratagem tunnelled centrally as alternative to taking it around either side (6)
10. Changing integral variable (8)
11. It's destructive to rubbish non-British in front of everyone (10)
12. This long is long, but not long enough! (4)
13,5ac. Vote in fine adjustment for hours typically (4 2 4)
15. In sty, over pig, pest getting ends off vents (10)
17. In Hunt, riders contrived something to be invested in (10)
19. Relax in 12, used to stripping (4)
21. Cycling amateurs, over-confident (4)
22. Significant author with article in Gulf Reform (10)
24. During those 13 months of parental preparation? (8)
25. Some current member, before following one (6)
26. People well lived, hence nearer various ends? (6)
27. Where you inhale salt as treatment for disease? (7)
Down:
2. Some bright sun a mild danger at the 27 (7)
3. Norma upset as Nina uses such 18s for the 12 ending (5)
4. Animals perhaps, returning text in heartless nastiness (9)
5. Utter some formula to turn back (5)
6. Single 5 down obtained joining 13 5 across with 'X'? (5-4)
7. Redesigned tin gave 12 of the grapes for instance (7)
8. A proxy aid organisation controlling visit in a way that doesn't seem right (13)
14. New way for men... Greece is coming out (9)
16. Untangle from sexy strip scam, step away with clothes (9)
18. For instance, 13 run lame after abuse (7)
20. What 6 is to 5 the 12 ending equals roughly 500 changing hands (7)
22. Stories which beat everyday boredom all ends up! (5)
23. Stares in wonder while turning pages (5)
Solution:
STARDOM==TOFIVE|
=S=O=R=P=O=O=I=|
NUTMEG=ALTERING|
=N=A=A=R=A=T=T=|
CANNONBALL=YEAR|
=M===I=D===F=G=|
NINE=STOVEPIPES|
===M=M=X=X=V===|
UNDERSHIRT=EASE|
=U=R===C=R===Q=|
SMUG=MEANINGFUL|
=E=E=Y=L=C=A=A=|
PRENATAL=AMPERE|
=A=C=H=Y=T=E=E=|
ELDERS==SEASIDE|
Name: 883 - 'X' Joined
Author: by BenDR

Annos-Across:
1. rev( MOD + RATS )
9. rev tel- (strata)GEM TUN(nelled) < , ext def
10. *INTEGRAL
11. CAN NON-B + ALL
12. YEAR(n) , ext def
13,5ac. *(VOTE IN FINE)
15. ST(y) OVE(r) PI(g) PES(t)
17. *(HUNT RIDERS)
19. (y)EA(r) (u)SE(d)
21. cyc( MUGS )
22. ME + AN IN + *GULF
24. *PARENTAL , ext def
25. ( MP + ERE ) after A
26. tails acrostic &lit
27. *DISEASE
Annos-Down:
2. tel (brigh)T SUN A MI(ld)
3. *NORMA
4. rev( SMS IN AG(g)RO )
5. rev tel (formu)LA TO T(urn) <
6. DD ("...joining nine to five with X" => "9 X 5" )
7. *(TIN GAVE)
8. CALL in *(A PROXY AID)
14. *(MEN GREECE)
16. (s)EX(y) (s)TRI(p) (s)CA(m) (s)TE(p)
18. *(RUN LAME)
20. *(EQUA(l->R)S) + D
22. rev tails acrostic &lit
23. *PAGES
Defs-Across:
1. Celebrity
9. alternative to taking it around either side
10. Changing
10. variable
11. It's destructive
12. This long
13,5ac. hours typically
15. vents
17. something to be invested in
19. Relax
21. over-confident
22. Significant
24. During those 13 months
25. Some current
26. People well lived, hence nearer various ends?
27. Where you inhale salt
Defs-Down:
2. danger at the 27
3. Nina uses such 18s for the 12 ending
4. Animals perhaps
5. Utter
6. Single
6. 5 down obtained joining 13 5 across with 'X'
7. 12 of the grapes for instance
8. in a way that doesn't seem right
14. coming out
16. Untangle
18. For instance, 13
20. What 6 is to 5 the 12 ending
22. Stories which beat everyday boredom all ends up!
23. Stares in wonder