Across:
1 Speculates (POSITS) symphonist fails to get hymn (‘symphonist’ fails to get ‘hymn’ = spoist = POSITS),
4 Elbow room (SPACE) at the counter (BAR) (SPACE BAR) in The Long Key (long key on a computer = SPACE BAR),
9 Clandestine (SECRET) group (S-ET) admits backing (= reversal indicator) church (Church of England = CE = -EC-) writing (from the 3Rs = -R-) (SECRET),
10 Makes fun of (PARODIES) music (‘rap’ music = PAR-) backing (= reversal indicator) on lyrical-poetry (-OD-ES) cover single (-I-) (PARODIES),
12 A type of holiday (BREAK-) popular before Easter (-FAST) (BREAKFAST) or at the end of 6 down, for instance (‘cook a meal’ = BREAKFAST),
13 Some gang’s terrorising (some ‘gangs terrorising’ = ANGST) out of a feeling of unease (ANGST),
14 Cracking jokes (GAGGING) to Commission (ORDER) (GAGGING ORDER) – that’ll shut them up! (GAGGING ORDER),
18 Complex (HARD) with best (top = TO P-) charter (-LEASE) (HARD TO PLEASE) is far too fussy (HARD TO PLEASE),
21 In the middle of (AMONG) overcompensating without optic nerves (‘overcompensating’ without ‘optic nerves’ = omang = AMONG),
22 Finishes Sangiovese, Sémillon (finishes ‘Sangiovese, Sémillon’ = EN-) and musty (= anagram indicator) Merlot (Merlot = -ROLME-T) around the end of autumn? (end of ‘autumn’ = -N) (ENROLMENT) That’s some admission! (ENROLMENT),
24 Resist the temptation (RESTRAIN) to show off (= anagram indicator) trainers (trainers = RESTRAIN),
25 Barman (Senior Counsel = SC-) from Trim (trim/edge = -HEM-) has a (-A) (SCHEMA) plan (SCHEMA),
26 Judge (CONCLUDE) or criminal? (CON-) The key (music key -D-) is in the hint! (-CLU-E) (CONCLUDE),
27 Temporary occupant (LESSEE) of port (port/left = L-) city in Germany (Essen) hasn’t finished (n) (‘Essen’ without ‘n’ = -ESSE-) engineering (-E) (LESSEE).
Down:
1 Support (support/pillar = POST-) case (-BAG-) at society (-S) (POSTBAGS) for man of letters (POSTBAGS),
2 Use a straw (SUCK) for the nog (EGGS used in eggnog/nog) (SUCK EGGS) and don’t tell your granny how to do it (don’t tell your granny how to SUCK EGGS),
3 Make adjustments (TWEAK) in time (T-) in firm? (infirm = -WEAK) (TWEAK),
5 Band Aid (PLASTER-) – is that what we most associate with Queen (-BOARD in chess) (PLASTERBOARD) or is that off the wall? (PLASTERBOARD),
6 Put in the oven (COOK A MEAL) old (-O-) glacial sand deposit (kame = -K A ME-) found in type of fuel (CO- -AL) (COOK A MEAL),
7 Leading The Blues (leading the ‘blues’ = B-) to The Hill’s (the hills = -RIDGE) (BRIDGE) central meeting point for The Liffeysiders, for example (BRIDGE),
8 Starts over (RESETS) in Spain (-E-) going into respite (rest = RES-T-) at top sanatorium (top ‘sanatorium’ = -S) (RESETS),
11 Failed to keep up (LAGGED BEHIND) with upsetting (= reversal indicator) settlement (deal = LA-ED) covering horse (-GG-) that’s overdue (BEHIND) (LAGGED BEHIND),
15 Maiden (INAUGURAL) from old city (-UR-) taken in by Guiana (Guiana = INAUG-A-) rogue (= anagram indicator) at port (port/left -L) (INAUGURAL),
16 See plans (see plans = PALENESS) changed (= anagram indicator) for lack of colour (PALENESS),
17 Local pressure from police department (HEAT) to renounce (“waive” = “-WAVE”) report (= homophone indicator) (HEATWAVE) of what The Sun’s fans are looking for (HEATWAVE),
19 Financial authority opens (‘financial authority’ = FA-) unfinished (k) building unit (‘brick’ without ‘k’ = -BRIC) (FABRIC), sold by the yard (FABRIC is sold by the yard),
20 It’s relative (COUSIN) to documentaries dismissing red meat? (‘documentaries’ dismissing ‘red meat’ = ocunis = COUSIN),
23 Heartless (a) place (‘lay’ without ‘a’ = LY-) by church (Church of England = -CE-) with English (-E) (LYCEE) and French school (LYCEE).