Across:
1 Takes up (= reverse indicator) good books (Old Testament = OT = -TO-) found in church (Roman Catholic = RC = -C-R-) with introductions to Ernest Hemingway’s (introductions to ‘Ernest Hemingways’ = EH – HE-) (HECTOR) hero who claimed Achilles was killing him? (Trojan hero Hector killed by Achilles = HECTOR),
4 Play emotional games with (PSYCH OUT) foreign (= anagram indicator) spy (spy = PSY-) caught (-C-) on bay (bay = shout) heading off (s) (‘shout’ without ‘s’ = -H OUT) (PSYCH OUT),
9 The Stones (GRAVEL) produced in the last place (GRAVE-) left (-L) (GRAVEL),
10 One making a film about characters (DIRECTOR) from cider (cider) mill (= anagram indicator) (cider = DIREC-) on hill (-TOR) (DIRECTOR),
12 Was responsible for the Molotov cocktail (MADE A BOMB) and got very rich (MADE A BOMB),
13 Cost (PRICE) of prima facie case failing to get Mafia aces (‘prima facie case’ failing to get ‘Mafia aces’ = price = PRICE),
14 Realises the error of one’s way (SEES THE LIGHT) in rant (seethe = SEE- THE) about Old Bob (old bob = shilling = -S) – a traffic controller (traffic LIGHT) (SEES THE LIGHT),
18 One (UNIT-) journalist (-ED) spells it out (STATES) (UNITED STATES) to us? (US = UNITED STATES),
21 Use 15 down perhaps (use ‘tin opener’ to UNCAP) to lift the lid (UNCAP),
22 Russia (RU-) runs (= anagram indicator) trials (trials = -RALIST-) at the foundation for indigenous (the foundation for ‘indigenouS’ = -S) (RURALISTS) countrymen (RURALISTS),
24 Local batter (local ‘batter’ = BEAT-) from Hull (hull/shell = skin) served up (= reverse indicator) (BEATNIKS) (skin = -NIKS) by non-conformists (BEATNIKS),
25 Small (S-) heads on termites, rhagoletis, obereas, katydid, earwigs, (heads on ‘Termites Rhagoletis Obereas Katydids Earwigs, = -TORKE) (STORKE) and one of the butterflies? (Butterfly STROKE in swimming),
26 Risk-takers (INSURERS) certainly (-SURE-) in (IN-) opening (= positional indicator) a fair amount of (half of) bars (half of ‘baRS’ = -RS) (INSURERS),
27 Minister (PRIEST) responsible for 1 down (PRIEST is responsible for ‘high mass’).
Down:
1 Service (HIGH MASS) of Provençal farmhouse (MAS-) in peak periods (highs = HIGH -S) (HIGH MASS),
2 Dealer in the docks supplies (dealer in the dock’s/ships’ supplies = CHANDLER) cocaine (C-) to spy’s boss (-HANDLER) (CHANDLER),
3 Some upsetting (= reverse indicator) nightmare possibly (some ‘nightmARE POssibly’ = arepo = OPERA) in Ring, for one (Ring OPERA),
5 Presumably, they made a packet (SHIPBUILDERS made a packet ship) for Noah’s family? (SHIPBUILDERS),
6 A low cutting remark (CHEAP SHOT) is typical of what’s on offer during the happy hour (CHEAP SHOT),
7 One of those from dress shop (OUTFIT) is not in (is OUT-) Trim (-FIT) (OUTFIT),
8 Regrettably ignores Beryl (‘regrettably’ ignores ‘Beryl’ = egrtta = TARGET) and Mark (mark = TARGET),
11 Polish (HONE -) saint (-ST) is a stocky figure perhaps (BROKER) (HONEST BROKER) and one having a reputation for impartial mediation (HONEST BROKER),
15 Can (TIN) Frank (OPEN-) Ward (-ER) (TIN OPENER) utilise this when working in the kitchen? (TIN OPENER),
16 Good books (Old Testament = OT-) on primarily (‘On’ primarily = -O-) terms of reference (-SCOPE) (OTOSCOPE) used by one involved in hearing cases? (OTOSCOPE),
17 In my opinion (AS I SEE IT), easiest (easiest) way (= anagram indicator) (easiest = AS I SEE -T) around island? (initial ‘Issue’ = I-) (AS I SEE IT),
19 Dad’s lover (MUM-) found at address in Salem (in Salem, India, a polite form of address = -BAI) (MUMBAI), an Indian city? (MUMBAI),
20 Design (= anagram indicator) canoes (canoes = OCEANS) for a number of different watery locations (OCEANS),
23 Fragment of aretalogy (fragment of ‘aRETALogy’ = retal) recedes (= reverse indicator) (retal = LATER) after a while (LATER).