No 13375, Tuesday 12 Oct 2021, Lightning

Solution to 18D 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.

ACROSS

1   Detective at emergency room left in dazed state (8) SHERLOCK {SH{ER}{L}OCK}

5   He often left mysterious events solved for starters (6) HOLMES Acrostic Semi&lit

9   Raincoat changed for Ivanisevic, perhaps (8) CROATIAN*

10 Finish off punch old teetotaller consumed to get drunk (6) BLOTTO {BL{O}{TT}Ow} 

12 Author to study at American university exiting Austria (5) DOYLE {DO}{YaLE}

13 Igloo gets built for expert on rocks (9) GEOLOGIST*

14 Leave someone helpless at thoroughfare in London (6) STRAND [DD]

16 Low-pitched sounds from horn damaged at church by one (7) RHONCHI {HORN*}{CH}{1}

19 Appreciates naval officer freeing a liberal at El Salvador (7) ADMIRES {ADMIRal}{ES}

21 Lane with sitar event — completely odd (6) STREET {SiTaR+EvEnT}

23 Extraordinary maid nearly grasps frameworks (9) PARADIGMS {MAID+GRASPs}*

25 Newton lost financier — one bringing dough (5) BAKER BAnKER

26 Hold on — one leaving child with one’s roommate (6) WATSON {WAiT}{SON}

27 Pose with hard worker after he becomes tentative (8) HESITANT {SIT}{ANT}<=>{HE}

28 Rigorous imprisonment further disheartened troublemaker (6) RIOTER {RI}{OThER}

29 One operating without ton of fish (8) STURGEON {S{T}URGEON}

DOWN

1   Formally withdraw from south eastern church with daughter and engineer (6) SECEDE {S}{E}{CE}{D}{E}

2   Yes, comets went to pieces in community (9) ECOSYSTEM*

3   Machine to cut short foam (5) LATHE LATHEr

4   Former tennis player editor transformed (7) CHANGED {CHANG}{ED}

6   First off prevent influence of painting material (3,6) OIL COLOUR {fOIL}{COLOUR}

7   Coniferous tree made appealing, taking away its tops (5) MATAI Acrostic

8   Worried, he omits old fruit drink (8) SMOOTHIE {HE+OMITS+O}*

11 Fellow on journey, missing the first boundary (4) FOUR {F}{tOUR}

15 A red room designed by engineer in facility for planes (9) AERODROME {A+RED+ROOM}*{E}

17 Restrain friend with move to end a game (9) CHECKMATE {CHECK}{MATE}

18 It may raise gent going up with force (8) ?A?P?W?R (Addendum - MANPOWER {POWER}<=>{MAN} - See comments)

20 Mark evidence (4) SIGN [DD]

21 Group receiving unique selling point with doubt (7) SUSPECT {S{USP}ECT}

22 Hundred going down for particle that may not be elementary! (6) PROTON {TON}<=>{PRO}

24 Proportion of limited food allowance (5) RATIO RATIOn

25 One interrupting supporter right by small shrub (5) BRIAR {BR{1}A}{R}

Reference List

Emergency room = ER, Left = L, Old = O, Teetotaller = TT, Austria = A, Church = CH, Liberal = L, Newton = N, Ton = T, South eastern = SE, Church = CE, Daughter = D, Engineer = E, Editor = ED, Fellow = F, Unque selling point = USP, Hundred = TON, Supporter = BRA, Right = R