No 12231, Saturday 03 Feb 2018, xChequer

Answer and annotation of 21d left for a rookie commenter till 10 AM.

Across

7. Sign when political affiliations switch in void (6) CANCEL {CANCE(-r+L)}
8. As though somewhere else there's millions in ready supply (8) DREAMILY {READY*} around {MIL}
9. Daisy's family member, female, always a handful (8) FEVERFEW {F}{EVER}{FEW}

10. Tick acknowledgement (6) CREDIT (DD)
11. Incontrovertible belief of setter, say abnormal chap (5) DOGMA {DOG}{MAn} (Abnormal = not normal=-n)
12. Wooden or concrete, getting broken with time (6) STOLID {S{T}OLID}
14. Place primarily to be covered, sense a deadline's involved going by this travel advice (3,6,3,3) SEE NAPLES AND DIE {SENSE+A+DEADLINE}* around {Place}
17. Obsessed with death, married men getting tender (6) MORBID {M}{OR}{BID}
18. Aged in relation to class (5) GRADE {~GREYED}
22. Criminal stuffing in loot gets a run of bad luck (6) HOODOO {HOOD}{lOOt}
23. Soak in river during dip, not easy when head is submerged (8) DRUNKARD {D{R}UNK}{hARD}
24. Trained nurse, after checking temperature, got cold sponge (8) SCROUNGE {NURSE+GOt+C}*
25. Foster home almost quiet (6) INSTIL {IN}{STILl}

Down

1. Minimum exposed, so be normal chaps (4,5) BARE BONES {BARE}{SO+BE+N}*
2. Riot with spade and pick (6) SCREAM {S}{CREAM}
3. Tory-Radical split (5) CLEFT {C}{LEFT}
4. The core of such plea: am wrong! (3,5) MEA CULPA {{sUCh}{PLEA}{AM}}* &lit
5. Sunk without a guide, deemed bad (8) EMBEDDED {DEEMED+BaD}
6. Faculty just tolerating student (5) FLAIR {F{L}AIR}
8. Fifty-fifty two? Hard days, need mild exercises (4,3,6) DOWN THE MIDDLE {TWO+H+D+NEED+MILD}*
13. One below par mostly without support, name's Charlie (9) BIRDBRAIN {BIRD{BRA}Ie}{N}
15. Imply importance by association with titled relations, mainly at work (4-4) NAME-DROP {NAME-D}{Relations}{OP}
16. Lifts large blocks wearing prison uniform (8) PURLOINS {PRISON+U} around {L}
19. Dashing ace Rishikesh sets, impossible he is forgotten (6) RAKISH {A+RISHiKesh}*
20. Put pressure on // ma? (5) FORCE (DD) (Force=MA based on Newton's second law of motion)
21. Close friend about to take leave with psychic instinct (5) ?U?I? HUMID {cHUM}{ID} See comments

Reference List
Millions=Mil, Female=F, Time=T, Married=M, Men=OR, River=R, Temperature=T, Cold=C, Home=In
Normal=N, Spade=S, Tory=C (Conservative), Radical=Left, Student=L (Learner), Hard=H, Days=D, Support=Bra, Name=N, Work=OP, Large=L, Uniform=U, Ace=A, About=C (Circa)

Colour/Font Scheme

Definition, Solution, Component letters, Embedded links, Anagram Indicator, C/C indicator, Reversal Indicator, Hidden word Indicator, Letter Pick indicator, Deletion Indicator, Homophone Indicator, Movement Indicator, Positional Indicator, Substitution, Indicator, Link/Connector, Extraneous

GRID