Across:
1 Hector (hector/jeer = -BOO-) found in bar (bar/block = BA-N) (BABOON) with primate (BABOON),
4 Cites (cites = IC- -EST) novel (= anagram indicator) about community (European Community = -E C-) hospital (-H-) (ICE CHEST) where you’ll find all those that are cold and drunk (ICE CHEST),
9 No-brainer dropping ban (‘no-brainer’ dropping ‘ban’ = oriner = RENOIR), as was known to have left an impression on the artistic movement (RENOIR),
10 Ultimate objective (GOAL-) to Tweet (-POST) (GOALPOST) from bar in the Aviva (GOALPOST),
12 Relatives of tea producer (CAMELLIAS) has the hump (CAMEL-) with America city (-L-A) over institute (-I-) and school (-S) (CAMELLIAS),
13 Reviewers dismiss The Wire (‘reviewers’ dismiss the ‘wire’ = veers = SEVER) in Split (SEVER),
14 Kowtow (kowtow = grovel = GR- -OVEL) over chap in (chap in = -APHIC N-) trouble? (= anagram indicator) (GRAPHIC NOVEL) That’s a comic story! (GRAPHIC NOVEL),
18 Part of the ticket (RUNNING MATES) for taking flight (RUNNING) with partners (MATES) (RUNNING MATES),
21 Release (UNTIE) documentaries cutting comrades (‘documentaries’ cutting ‘comrades’ = untie = UNTIE),
22 The neighbour’s (EUROPEANS) poles? (Poles = EUROPEANS),
24 Put down (BADMOUTH) awful (BAD-) starter of moussaka (starter of ‘moussaka’ = -M-) on holiday (-OUT-) at hotel (-H) (BADMOUTH),
25 Twist (TANGLE) for drunk (= anagram indicator) agent (agent = TANG-E) consuming port (port/left = -L-) (TANGLE),
26 Officer (Officer Commanding = -OC-) on weekend (‘week’ end = -K-) consumed by Bowie (Bowie knife/blade = BL-ADE) (BLOCKADE) in bar (BLOCKADE),
27 Clandestine (SECRET) group (S-ET) admits backing (= reversal indicator) church (Church of England = CE = -EC-) writing (from the 3Rs = -R-) (SECRET).
Down:
1 Robin (BIRD-) is hesitant about committing (cagey) briefly (y) (‘cagey’ without ‘y’ = -CAGE) (BIRDCAGE) to accommodation synonymous with flighty type (BIRDCAGE),
2 A dog’s dinner perhaps (bone meal = BONEMEAL)) for those who know their onions and what helps them grow (BONEMEAL fertiliser),
3 Hotelier takes out the (‘hotelier’ takes out ‘the’ = olier = ORIEL) bay window (ORIEL),
5 Race (CROSS-COUNTRY) of angry (CROSS-) people (-COUNTRY) (CROSS -COUNTRY),
6 Business (CO-) union (European Union = -EU-) after (= positional indicator) bereavement (-LOSS-) go to Mass (-M) (COLOSSEUM) in Rome’s landmark setting (COLOSSEUM),
7 Transfer Power (transfer power = devolve) without an introductory letter (d) (‘devolve’ without ‘d’ = EVOLVE) to make progress (EVOLVE),
8 Trout (trout = TUTOR-) swimming (= anagram indicator) ahead of salmon (ahead of ‘salmon’ = -S) (TUTORS) in school (TUTORS),
11 Nearly all (c) the record (‘disc’ without ‘c’ = DIS-) is taped (-CONNECTED) (DISCONNECTED) and it’s unplugged (DISCONNECTED),
15 Cleaning out The Kitchen Cabinet, for example (HOUSEWORK), in Dáil (HOUSE-) and get to earn one’s living (-WORK) (HOUSEWORK),
16 Funny (STRANGE-) writing (from 3Rs = -R) (STRANGER) in The Outsider (STRANGER),
17 From my view (AS I SEE IT), drunk (= anagram indicator) Asti (Asti= AS I -T) going around Mediterranean (Mediterranean ‘Sea’ = ‘SEE’) state (= homophone indicator) and island (I) (AS I SEE IT),
19 Loud noise (HUBBUB) from Trim (t) shelter (‘hut’ without ‘t’ = HU-) beside guest house (B & B = -BB-) with bar (pub) needing no introduction (p) (‘pub’ without ‘p’ = -UB) (HUBBUB),
20 Followed suit without fellow (‘followed suit’ without ‘fellow’ = odsuit = STUDIO) from workshop (STUDIO),
23 Parking (P-) on narrow street (-LANE) (PLANE) on a flat surface (PLANE).