No.11284, Monday 05 Jan 2015, Gridman

A wower from Gridman, with 23a as my COD

Across
1 With old pound recalled, you get unwanted repercussion (8) BLOWBACK ((W O LB)<)
5 Casual clothes for old soldiers (6) SWEATS (2)
9 One to get one new, novel immune system booster (7) ANTIGEN (AN GET I N)*
10 Word for word mistake (7) LITERAL (CD)
11 Press follows second side for a pressing need (5,4) STEAM IRON (S TEAM IRON)
          Reminded of a classic pun from Wodehouse - The Mating Season: 
         “You can't press your suit and another fellow's trousers simultaneously."
12 Sari, maybe - no small spread-out (5) DRAPE (SPREAD-S)*
13 Wary about how things may go bad sometimes (4) AWRY (WARY)*
           And as the poet Burns puts it: "They gang agley"
14 A space for twisted bale could have been averted (9) AVOIDABLE (A VOID BALE*)
17 Typically, over time a girl enters (2,7) ON AVERAGE (ON AGE around VERA)
19 Mark, prince's descended from the cliff (4) SCAR (SCARP -P)
23 Mother, mother, mother, mother (5) MAMMA (MA M MA)  for defn. take any of the two extreme mothers. Please highlight your choice.
       Reminded me of the Wodehousian characters who go "Hullo, hullo, hullo" and as if that is not enough, add a couple more of those hullos for good measure.
24 Aim is to be camping, working after lunchtime (9) INTENTION (IN TENT, ON after I)
25 An officer who isn't particular (7) GENERAL (CD,DD)
26 Old British coin taken finally by African national (7) GUINEAN (GUINEA coiN takeN) See comments
27 Having refinements in Nice, say (2,4) DE LUXE (CD)
28 With frenetic paces carried out now, one finally has a wild adventure (8) ESCAPADE (PACES* around AD, onE)

Down
1 Supports small cover for top military officer (5,3) BRASS HAT (BRAS S HAT)
          The Gridman touch ! ;-)
2 Become drained? With some re-positioning of parts, last longer! (7) OUTWEAR (WEAR <-> OUT)
3 Grown-up girl's participation in more than one match (6) BIGAMY (BIG AMY)
4 Distributing viler cartoons is disputable (13) CONTROVERSIAL (VILER CARTOONS)*
6 And doctor with a wife is to back out (8) WITHDRAW (WITH DR A Wife)
7 High-flown correspondence? (7) AIRMAIL (CD)
8 Ire caused by peels strewn at entrance to necropolis (6) SPLEEN (PEELS)*
10 Some pauses in between flights (7,6) LANDING STAGES (CD)
15 A Roman road heard fast ones of female pilot (8) AVIATRIX (A VIA ~TRICKS)
          Remembered Pussy Galore in Goldfinger. Gert Frobe, who played the pompous Prussian office in Those Magnificient Men in their Flying Machine, played Goldfinger
16 Nothing's right. A social welcomes new munitions (8) ORDNANCE (O R DANCE around N)
18 No mail strewn carelessly around town-end is insignificant (7) NOMINAL  ((NO MAIL)* around towN)
20 Fancy ring for artist (7) CHIMERA (CHIME RA)
21 Setter's admission of being old is projected (6) IMAGED (I'M AGED)
          Gridman? Old? I don't think so!
22 Complaint of pain from a new Italian actress (6) ANGINA (A N GINA)
          Can't forget Luigina's famous line from Come September: "I don't have to make sense. I'm Italian!)

GRID