No 11440, Tuesday 07 Jul 2015, Incognito

ACROSS
8   I left corn labyrinth (4) MAZE MAiZE
9   This author (Mary Pollock) might be let in by Don (4,6) ENID BLYTON {LET+IN+BY+DON}*
10 Saif returned before company's ruin (6) FIASCO {FIAS<=}{CO}
11 It is a type of table — made from fall foliage (4-4)  DROP-LEAF {DROP}-{LEAF}

12 No tirade follows senior policeman lacking knowledge (8) IGNORANT {IG}{NO}{RANT}
14 “Containerised tree is good for the French”, said endlessly (6) BONSAI {BON}{sAId} Correction - {BON}{SAId}

16 Outlandish wolf's bird (4) FOWL*
17 Grand improvised explosive device, in the beginning, has unknown composite (5) MIXED {M}{I{X}ED} 'in the beginning' is superfluous as IED is a recognised abvn
18 Nun's cap's made mostly from coir by female (4) COIF {COIr}{F}

19 I, in Germany, followed soldiers with Indian martial art technique (3,3) TAI CHI {TA}{I CH}{I}
21 Triumph over peak after some usual mistakes initially (8) SURMOUNT {Some}{Usual}{R}{MOUNT} Source of  R not clear. Seems to be an error as 'mistakes' has no role in the clue.
23 “Oh-di-lay-ee-ay, di-lay-dee-oh, de-lay-ee,” sings he, “Howler around full moon day” (8) YODELLER {Y{O}{D}ELLER}
26 So, remove the air-conditioner! Truth remains truth! (6) VERITY VERacITY
27 Fiat's in intersection (10) INJUNCTION {IN}{JUNCTION}
28 Instrument has ring before open end, for starters (4) OBOE {O}{B}{O}{E}

DOWN
1   First bachelor, and then monarch takes aerated water to make sodium bicarbonate (6,4) BAKING SODA {BA}{KING} {SODA}
2   Tax on water body's store of sewage (8) CESSPOOL {CESS}{POOL}
3   It is a hat made of iron by artists after party (6) FEDORA {FE}{DO}{RA}

4   Equable mother-in-law and daughter (4) MILD {M-I-L}{D}
5   Taken in by sailors or engineer before commencement of dinner (8) ABSORBED {ABS}{OR}{BE}{Di...r}
6   Half of yellow matter found in half-minced matter is nerve insulation (6) MYELIN {M{YELlow}INced}
7   Considerably small quantity, like “I” to a Greek? (4) IOTA {I}{TO+A}* &lit
13 Reassessment of taxes in American state (5) TEXAS*
15 Outer space creature hovers over leaderless country leading to estrangement (10) ALIENATION {ALIEN}{nATION}
17 Spread oil in a mica construction to make some pottery (8) MAIOLICA {OIL}* in {A+MICA}*

Cartoon by Bhargav

18 Singer, perhaps, is friend of one royal lad (8) CHOIRBOY {CH}{O}{1}{R}{BOY} O for of? Source of CH was explained by Incognito in the comments yesterday.
20 What?! Spanish revolutionary went ahead and got a monetary instrument?! (6) CHEQUE {CHE}{QUE}
22 Old god's creeper's canyon (6) RAVINE {RA}{VINE}
24 Round 1: New King's pig's sound (4) OINK {O}{1}{N}{K}
25 Drops from the sky in Naraingarh (4) RAIN [T]

Reference list

Grand = M, Soldiers = TA(Territorial Army), Day = D, Ring = O, Artists = RA, Party = DO, Daughter = D, Sailor = AB, Engineer = BE, Of = O?, Royal = R, King = K

GRID