No 11500, Tuesday 15 Sep 2015, Skuldugger

Too obscure to be doing, early in the morning, at the airport! The NW corner has be foxed.

ACROSS
1   Gradually, Italian co-ops reordered boxed English article (4,1,4) POCO A POCO Anno to be given by any commenter  (Addendum - {COOP}* {A} {COOP}* - See comments)
6   Mischievous sprite has plum cake regularly (4) PUCK {PlUm}{CaKe}
8   Lively dance by girl with sporadic interest (romantic chiefly) in boy (8) GALLOPED Anno pending (Addendum - GALLIARD - {GAL}{L{I}A{Ro...c}D} - See comments)
9   In which the 11 is not very accommodating: heart of Tartarus (6) DETAIL {DE(-v+ta)TAIL}
10 A giant Airbus fan malfunction might be one heck of a deal (8,7) FAUSTIAN BARGAIN {A+GIANT+AIRBUS+FAN}*
11 “Unadulterated evil” describes underworld boss (5) DEVIL [T]
13 Spooner's firework plant (8) LARKSPUR from SPARKLER

15 Hottest Serrano peppers initially far from hot (8) SPICIEST {Se...o}{Pe...s}{ICIEST}
18 After death, spirit appears in Hades following typo (5) SHADE* (Addendum - (+s)SHADE(-s) - See comments)
20 11ish phosphate in lime compound (15) MEPHISTOPHELIAN*
23 Nonsense spouted by bookish characters on a bender after love-loss? (6) KIBOSH BOoKISH*
24 Slips careless, dropping last two at Ashes final (8) NEGLIGES {NEGLIGEnt}{S}
25 Little 11s instigating minor, paltry sins chiefly (4) IMPS Acrostic
26 An exotic bloom profaned her bodice (3,6) BEE ORCHID*

DOWN
1   11's preferred fashion brand excellent, Dad admits (5) PRADA ? (Addendum - {P{RAD}A} - See comments)
2   Little officer is so revolutionary in Gargantua and Pantagruel, for instance (7) COLOSSI {COL}{OSSI<=}
3   Setter takes taxi at the beginning of autumn, returns in the summers (5) ABACI {n...uA}{BAC}{I}<=
4   Could be thirteenth nobleman beheaded in the heart of Male (7) ORDINAL {lORD}{IN}{mALe}
5   12 for 11 or 'hardly improved' (3,5) OLD HARRY*
6   Cauldron takes forever to make soups (7) POTAGES {POT}{AGES}
7   Wept, overwhelmed, quit performing for being judged (9) CRITIQUED {CRI{QUIT*}ED}
12 Crumbling empire turning to mush after king kicked the bucket, for instance (9) EUPHEMISM Anno left for any commenter (Addendum - {EMPIrE+MUSH}* - See comments)
14 Married British leader concealed terrible shame — an Indian mistress (8) MEMSAHIB {M}{SHAME*}{I}{B}
16 Upset ejaculation breaks musical partnership (7) CAHOOTS Anno left for any commenter (Addendum - {CA{HOO<=}TS} - See comments)
17 Beat badly, centurions in hostilities finally decamp (7) TROUNCE CENTURiOns*
19 The bloke's gained a couple of pounds, he has no energy and is extremely unpleasant (7) HELLISH {HE{LL}IS}{He}
21 Voracity without moderation ultimately results in more fat (5) HUGER HUnGER
22 Change effected by people in this day and age (5) AMEND {A{MEN}D}

GRID