Solution to 17A has been deliberately left unsolved and is to be answered only by a non-regular / novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
Open for anyone to solve, if not solved by 1 PM.
ACROSS
8 Spooner's stomach aid for gymnastic posture (9) HANDSTAND {~stand hand to handstand)
9 First to last, dirty paintings (4) OILS (-s)OIL(+s)S
10 Rugby Union team rep, lively, consumed by disposition to be feverish (3,1,11) RUN A TEMPERATURE {RU} and {TEAM+REP}* in {NATURE}
12 Abnormally thin English couple catching a cold, one died (9) EMACIATED {E}{MA{C}{1}ATE}{D}
13 Record ton on batting left-handed (5) INEPT {EP}{T}<=>{IN}
14 Observant, required when husband replaces note (7) HEEDFUL (-n+h)HEEDFUL
17 European cycling champs are superior in organisation (7) M?N?G?R (Addendum - MANAGER {(-ger)MAN(+ger)GER} over {A} - See comments)
19 Regrets circumventing lecturer's principles (5) RULES {RU{L}ES}
21 Wretched p
lace concealing start of
potential
viral disease (9)
VARICELLA {
pLACE+VIRAL}*
24 Model of one, expect I am in line for this? (15) EXEMPLIFICATION {OF+1+EXPECT+I+AM+IN+L}* &lit
25 Discharge brat (4) SNOT [DD]
26 Monotone, one curiously odd? Yes, strangely delivered (9) UNICOLOUR {ONe+CURIOUsLy}*
DOWN
1
Chore rashly done ending in acut
e muscle cramp (7,5)
CHARLEY HORSE {
CHORE+RASHLY+donE} (Correction - {CHORE+RASHLY}*{
a..tE} - See comments)
2 One nobody picked up before steady flood (8) INUNDATE {1}{(~none)NUN}{DATE}
3
African thug climbing th
is to start casing section (6)
TSOTSI [T<=]
4
Rodent damage mounting
to millions (6)
MARMOT {MAR} and {TO}{M}<=
5
Damn dude, lousy
rider (8)
ADDENDUM*
6 Spot of balm coating bit of chapped area (8) LOCATION {LO{Ch...d}{A}TION}
7 Top bishop, contemptible person (6) BLOUSE {B}{LOUSE}
11 Performers in street near ground (12) ENTERTAINERS*
15 Fellow ends up supporting American nit-pickers (8) FUSSPOTS {F}{STOPS<=}<=>{US}
16 Setter's entering inebriated party (4,2,2) LIVE IT UP {L{I'VE}IT UP}
18 Delay over
pilot flying
crock for drugs (8)
GALLIPOT {LAG<=}{PILOT*}
20 First infiltrates security,
seconds later
stays under cover? (3-3)
LIE-INS {LIE{1}N}{S}
22
Sultana's rule reportedly saving lives (6)
RAISIN {(~reign)RAIN} over {IS}
23
Don quickly reversing operation divides family (4,2)
CLAP ON {CLA{OP<=}N}
Reference List
Rugby Union = RU, English = E, Cold = C, Died = D, Record = EP(Extended Play), Ton = T, Batting = IN, Husband = H, Note = N, Are = A, Lecturer = L, Line = L, Steady = DATE, Millions = M, Area = A, Bishop = B, Fellow = F, Seconds = S