Across:
1 Irish dance (JIG-) was (was) set up (= reversal indicator) (was = -SAW) (JIGSAW) by one of those types cutting corners (JIGSAW machine for cutting),
4 Colas I (colas I) drunk (= anagram indicator) (colas I = SOCIA-L-) contains vitamin (-B-) energy (-E) (SOCIABLE) cordial (SOCIABLE),
9 Charm (ALLURE) of spring (= anagram indicator) laurel (laurel = ALLURE).
10 Better half (HELPMATE) of support (HELP-) for Buddy (-MATE) (HELPMATE),
12 Officer (Officer Commanding = OC-) from church (-CULT-) gets university award (first = 1ST = -IST) (OCCULTIST) for playing the devil’s advocate perhaps (OCCULTIST),
13 Duck (O-) liver (liver) is not finished (r) (‘liver’ without ‘r’ = -LIVE) (OLIVE) by one of The Greens (OLIVE),
14 One of those in the gym (SKIPPING ROPE) is missing (SKIPPING) one of those from Ring (ROPE from boxing ring) (SKIPPING ROPE),
18 Fitting pastime perhaps (JIGSAW PUZZLE) for those in 1 across (‘jigsaw’ = JIGSAW) and 19 down (‘puzzle’ = PUZZLE) (JIGSAW PUZZLE),
21 Country (USA-), for example (e.g.), brings up (= reverse indicator) (e.g. = -GE) (USAGE) the matter of consumption (USAGE),
22 It’s wrong (sin = SIN-) getting drug (-E-) treatment (-CURE-) on bender (-S bend) (SINECURES) – is that to work with soft options? (easy jobs/cushy numbers = SINECURES),
24 Final (Z-) Nazi (Nazi) stupidity? (= anagram indicator) (Nazi = ANZI-) Keep out of (-BAR) (ZANZIBAR) island! (ZANZIBAR),
25 Florentine removes trio (‘Florentine’ removes ‘trio’ = flenne = FENNEL) from herb garden (FENNEL),
26 Late in the day (EVENTIDE), papers (-ID- papers) arrive after (= position indicator) incident (EVENT-) at The Point (compass point East = -E) (EVENTIDE),
27 Apologists dismiss a lot (‘apologists’ dismiss ‘a lot’ = pogiss = GOSSIP) of tittle-tattle (GOSSIP).
Down:
1 In France, John (John = Jean) isn’t finished (n) (‘Jean” without ‘n’ = JEA-) with awful (-LOUSY) (JEALOUSY) resentment (JEALOUSY),
2 Party (GALA-) for college (-C-) jerk (-TIC) (GALACTIC) is out of this world (solar system / galaxies = GALACTIC),
3 Laura (Laura) plays (= anagram indicator) (Laura = AURAL) acoustic (AURAL),
5 Bringing down royalty (OVERTHROWING) to open (OVERT-) hotel (-H-) that appeals to sporty types pulling a few strokes perhaps (-ROWING) (OVERTHROWING),
6 I am (I am = I’m = IM-) going to jog memory (-PROMPT-) at the youth centre (‘yoUth’ centre = -U) (IMPROMPTU) and ad-lib (IMPROMPTU),
7 Raises (= reverse indicator) reptile (lizard) briefly (d) (‘lizard’ without ‘d’ = lizar = -RAZIL) at the top of the bay (at the top of the ‘Bay’ = B-) (BRAZIL) in South America (BRAZIL),
8 Look out for (EYE-) the French (the = -LE-) toast starter (‘Toast’ starter = -T) (EYELET), as it’s not typical in Wellington? (EYELET not typical on Wellington boot)
11 Observe (WITNESS) in Croke Park (STAND) (WITNESS STAND) or in court in America that involves a brief encounter (WITNESS STAND),
15 The producer says he has to hand it to the consumer (PRICE LIST), as it’s the cost (PRICE) of getting Liszt (Liszt) on the radio (= homophone indicator) (‘Liszt’ = ‘LIST’) (PRICE LIST),
16 Important old Russians (CZARINAS) in Nazi cars (Nazi cars) out of place (= anagram indicator) (Nazi cars = CZARINAS),
17 Gives away (LETS SLIP) accommodation (LET-) on ship (SS = -S S-) – is that something to gloss over? (-LIP) (LETS SLIP),
19 This is one (PUZZLE) tough conundrum, for instance (PUZZLE),
20 Local snack (‘local’ sandwich = SARNIE) for Old Bob (old bob = shilling = S-) Arnold (-ARNIE) (SARNIE),
23 The belief is (CREDO), there’s no gas to be found in God’s acre (no ‘gas’ to be found in ‘Gods acre’ = odcre = CREDO).