Across:
1 Head to head (head to ‘head’ = H-) with theologian (Doctor of Divinity = -DD-) in university (University of Limerick = -U-L-) from English (-E) (HUDDLE) flock (HUDDLE),
4 At the back of the lounge (at the back of the ‘lounge’ = E-) drunk (-SOT-) is a guy (-ERIC) (ESOTERIC) understood by very few (ESOTERIC),
9 Copyright (C-) niggles (-ACHES) (CACHES) those secretive computer types (CACHES),
10 Notices in the paper (SMALL ADS) what’s insignificant (SMALL) to a (A-) policeman (detective sergeant = -DS) (SMALL ADS),
12 Charlie (-C-) found in stretch of water (S-OUND-) with a fair amount of (half of) relief (‘half of relief’ = REL) (SCOUNDREL) by rogue (SCOUNDREL),
13 Love bites best ignored (‘love bites’ ‘best’ ignored/without ‘best’ = lovei = OLIVE), as that one’s a bit green (OLIVE),
14 Turns (wheels = WHEEL-S) over one of the sister’s flowers (flower/River -BARROW = one of the “Three Sisters”) (WHEELBARROWS) used by the gardeners (WHEELBARROWS),
18 For the national players (ABBEY THEATRE), they have one of those in 27 across (one of ‘stages’ and ABBEY THEATRE has a stage),
21 Crisis (DRAMA) witnessed in 18 across, for example (DRAMA witnessed in ‘Abbey Theatre),
22 Protected (SHELTERED) the elders (the elders = SHELTERED) all over the place (= anagram indicator),
24 Committed oneself (PROMISED) to text (prose = PRO-SE-) about most of (x) the composition (‘mix’ without ‘x’ = -MI-) from Dublin (-D) (PROMISED),
25 Case in point – ignore spice (‘case in point’ ignore ‘spice’ = ainont = NATION) from India, for one (NATION),
26 Made a fuss about (STRESSED) (desserts = STRESSED) sent back (= reversal indicator),
27 Puts on (STAGES) gates (gates = STAGE-) roughly (= anagram indicator) at school (-S) (STAGES).
Down:
1 They tend to cut (HACKSAWS) journalist’s (hack’s = HACKS-) article (-A-) on leaders of white supremacy (leaders of ‘white supremacy’ = -WS) (HACKSAWS),
2 Did the new mix (DOCTORED) for Alerted Images, for instance (DOCTORED),
3 Stay under the covers (LIE-IN) finishing (= position indicator) popular (IN) fiction (LIE-) (LIE-IN),
5 It’s much the same (SIMILAR-) for one (-I-) getting draws (-TIES) (SIMILARITIES) from matches (SIMILARITIES),
6 Storyline from Misery (TALE OF WOE) is a parable that will make you cry (TALE OF WOE),
7 Radio (radio = ROADI-) wave (= anagram indicator) is key (music key -E) (ROADIE) to setting up a musical band (ROADIE),
8 Ruminate (C-HEW) over a (-A-) small (-S-) (CASHEW) nut (CASHEW),
11 What the players could do (CREATE A SCENE) to cause trouble publicly (CREATE A SCENE),
15 Cock and bull stories (lies = L-IES) about one (-I-) offering support to a woman (-BRA-), writing (from the 3Rs = -R-) (LIBRARIES) to those offering loans on the books (LIBRARIES),
16 Police operation (ST-ING) captures a (-A-) recreational vehicle (-RV-) (STARVING) running on empty (STARVING),
17 Lines above text (HEADINGS) from dashing (dashing = H-ADINGS) model (= anagram indicator) taking in Spain (-E-) (HEADINGS),
19 Puts own stamp on (ADAPTS) fancy (= anagram indicator) tapas (tapas = A-APTS) around starter dish (starter ‘dish’ = -D-) (ADAPTS),
20 The angel’s share perhaps (“the angel’s share” is what evaporates when alcohol is being aged in barrels / VAPOUR) in most of (t) the barrel (‘vat’ without ‘t’ = VA-) with port (-P-) is acidic (sour) when top is taken off (s) (‘sour’ without ‘s’ = -OUR) (VAPOUR),
23 Tribute (TOAST) to water tester (toe) nearly (e) (‘toe’ without ‘e’ = TO-) getting endless (i) fizz (‘Asti’ without ‘i’ = -AST) (TOAST).