ACROSS
 1. /10. "SHAM PAIN" SO CIA LIST = CHAMPAGNE SOCIALIST <rich left-winger>
 6. BAN outside CO = BACON <rasher?>
 9. E inside NATO = NEATO <cool>
10. [see 1 Across]
11. <high opinion> ESTEEM = ←MEETS E←
12. QUI + ÉTUDE = QUIETUDE <peaceful atmosphere>
14. <excess> SUPERFLUITY = "SYRUP FUTILE"
16. <don't let others use> HOG <motorcycle>
18. <prosecute> SUE = S_ ←EU←
19. <bureaucrat> FUNCTIONARY = FURY outside (ANTI-CON)*
21. <flatfish> FLOUNDER <flop around>
22. <bomb> STRAFE = SAFE outside T_R
25. FRANCE outside HIS = FRANCHISE <right to vote>
26. <Ancient Britons> ICENI = "EYE SEA NIGH"
27. <frost-resistant> HARDY = HYDRA*
28. <seaduck> GOLDENEYE = GO + LD ENE _Y _E

DOWN
 1. ONS inside CENSUS = CONSENSUS <agreement>
 2. <expect> AWAIT = A WIT outside _A_
 3. <trailblazer> PIONEER = PI (NEE inside O_R)
 4. GAS + H = GASH <injury>
 5. EX CRU CITE outside A = EXCRUCIATE <rack>
 6. BRA VERY = BRAVERY <daring>
 7. CHI (_H_ U_A)² = CHIHUAHUA <Mexican state>
 8. NIT R_E = NITRE <fertiliser>
13. <being tactless> BLUNDERING = UNDER inside BLING
15. <Jurassic reptile> PTEROSAUR = "TERROR SOAR"
17. <antifreeze> GLYCERINE = GENERICALLY* - AL
19. <particular> FINICKY = FIN ICKY
20. <last longer than> OUTLIVE = OLIVE outside UT
21. (.e)F IF TH(e.) = FIFTH <musical interval>
23. A_ R_ E_ T_ E_ = ARETE <Greek virtue>
24. "REAL" = REEL <segment of film>