No 11790, Tuesday 30 Aug 2016, Arden

ACROSS
1   Perhaps Iodine turns deep blue (8) SAPPHIRE {PERHAPS+I}*

5   Slender, not small — favourite of mine (6) LIMPET {sLIM}{PET}

10 Cover over Jane Austen's book maybe 'to be or not to be' (7) DILEMMA {LID<=}{EMMA}
11 Works in a company — is getting some capital (7) NICOSIA {IN+A+CO+IS}*
12 One from part of Karnataka, say, missing old dog (5) CORGI COoRG1

13 Kremlin's striking feature perhaps — I'm on one holding a party (5,4) ONION DOME {I'M+ON+ONE}* over {DO}

14 They believe everyone's equal over time – unruly Italians block road (12) EGALITARIANS {AGE<=}{LITA{R}IANS*}
18 One's responsible as one turns out to be crazy (12) INSTRUMENTAL {1+TURNS}*{MENTAL}
21 Bird picks most of the fruit without remorse (9) GUILLEMOT {LEMOn} in {GUILT}

23 First ring in, ring out and grind into small balls (5) PEARL {PEA{Ring}L}
24 It's true — paper back is a source of poison (7) REALGAR {REAL}{RAG<=}

25 Give the Spanish wine before first course (7) ELASTIC {EL}{ASTI}{Co...e}
26 However, makes it equal to zero (4,2) EVEN SO {EVEN S}{O}
27 Geological equilibrium, say — it's so unstable (8) ISOSTASY*

DOWN
1   Spoke on service, reportedly to tempt (6) SEDUCE {~ said){SED}{UCE}(~ use}
2   Not enough to go with friend (6) PALTRY {PAL}{TRY}
3   Lulu sounds half German (9) HUMDINGER {HUM}{DIN}{GERman}
4   Data bank found just after you go through a note online (4-4,6) READ-ONLY MEMORY {READ}-{ONLY} {MEMO}{RY}
6   Old South American ancestry will throw some light (5) INCAN INCANdescent
7   History by word of mouth on the countryside (8) PASTORAL {PAST}{ORAL}
8   Tramlines don't allow man to go across (8) TRAVERSE {TRAm}{VERSE}
9   Dimness in disc isn't sent away (14) INDISTINCTNESS*
15 Comes back with cut fruits (9) REAPPEARS {REAP}{PEARS}
16 Something unmentionable as evergreen lake (8) LINGERIE {LING}{ERIE}
17 Reckon it's back after Middlesex team is formed (8) ESTIMATE {sEx+TEAM+IS}* (Addendum - (sEx}{IT'S<=}{TEAM}* - See comments)
19 It's repeated by some German trade delegation (6) MANTRA [T]
20 Gritty and first person to be so fortunate (6) PLUCKY {Pe...n}{LUCKY}
22 Reason for girl to raise capital (5) LAGOS {SO}{GAL}<=

GRID