Across:
1 In retrospect (= reversal indicator), writer (ed = D-E) goes around eatery (café = -EFAC-) (DEFACE) with Sully (sully/damage = DEFACE),
4 EU dismissed by unsuitable (‘EU’ dismissed by ‘unsuitable’ = unsitabl = ISTANBUL) old capital (ISTANBUL),
9 Institute (-I-) in Newry (Newry) moving (= anagram indicator) (Newry = W-NERY) (WINERY) business responsible for developing port (WINERY),
10 Wise guy (sage) loses the head (sage’ without ‘s’ = AGE) – it’s the last straw (LIMIT) (AGE LIMIT) for the bar restricting entry (AGE LIMIT),
12 Describes an unsociable flight (FLIES SOLO) with pests (FLIES) from Oslo (Oslo) all over the place (= anagram indicator) (Oslo = SOLO) (FLIES SOLO),
13 Some of Ulysses particularly (some of ‘ulysSES PArticularly’ = sespa = APSES) upsetting (= reverse indicator) those in the church (APSES),
14 Burst a blood vessel (LOSE PATIENCE) by the sound of it (= homophone indicator), when the doctors can’t find who is sick (‘lose patients’ = ‘LOSE PATIENCE’),
18 Get hot and bothered (LOSE ONE’S COOL) opening 14 across (opening ‘lose patience = LOSE) in the middle of 5 down (in the middle of ‘sign one’s name’ = ONE’S) with it? (COOL) (LOSE ONE’S COOL),
21 Deliberately gets rid of Bradley (‘deliberately’ gets rid of ‘Bradley’ = eliet = ELITE) from select group (ELITE),
22 Rocky (= anagram indicator) Madison is (Madison is = ADMISSION) in confession (ADMISSION),
24 Brings to light (UNEARTHS) close to (-NEAR-) the (the) dock (dock/remove ‘e’) (‘ the’ without ‘e’ = -TH-) in America (US = U-S) (UNEARTHS),
25 Turns up (= reversal indicator), genetic evidence (DNA = -AND) found on top of the ground (top of ‘Ground’ = -G-) in Australia (AU = U-A) (UGANDA) and in Africa (UGANDA),
26 Friend (pal) turns over (= reversal indicator) (pal = LAP-) papers (-ID- papers) – for half a salary (half a ‘salARY’ = -ARY) (LAPIDARY), job might mean taking a shine to rocky types (polishing / cutting stone = LAPIDARY),
27 Exchanged for money (-SOLD-) in Ireland (Ireland domain = .ie = I-E) (ISOLDE) by Tristan’s lover (ISOLDE).
Down:
1 Ruin (DOWNFALL) in Ulster (DOWN-) has nothing to do with The Rising (-FALL) (DOWNFALL),
2 A French (‘a’ French = -UN-) and a German (‘a’ German = ein) reflection (= reverse indicator) (ein = -NIE-) by Old Bob (‘old bob’ = shilling = -S-) in the paper (Financial Times = F-T) (FUNNIEST) is most amusing (FUNNIEST),
3 Public relations officer (Public Relations Officer = PRO) takes a turn (= reversal indicator) (PRO = -ORP-) in civil service (C-S) (CORPS) unit (CORPS),
5 Individuals (ones = ONE’S) following (= position indicator) most of 23 down (most of ‘signs’ = SIGN) for celebrity (NAME) (SIGN ONE’S NAME) autograph (SIGN ONE’S NAME),
6 Joins in case (in case = -IANCES) criminal (= anagram indicator) is after (= position indicator) everyone (ALL-) (ALLIANCES) from the unions (ALLIANCES),
7 Confuse (BEMUSE) honey producer (bee = BE-E) welcoming some (some) revolutionary (= reverse indicator) report (= homophone indicator) (‘some’ = ‘sum’ = -MUS-) (BEMUSE),
8 The foreign (the = LA-) investigation (-TEST) (LATEST) is in Vogue (LATEST),
11 Local courage (BOTTLE -) by that woman (-SHE-) in major conflict (war = WA-R) (BOTTLE-WASHER) – a partner of chief cook (“chief cook and BOTTLE-WASHER”),
15 Old-age pensioner dismissing slogan (‘old-age pensioner’ dismissing ‘slogan’ = depeioner = PIONEERED) broke new ground (PIONEERED),
16 Latino on (Latino on) tour (= anagram indicator) (Latino on = NOTIONAL), in theory only (NOTIONAL),
17 Draw out (ELONGATE) sweetheart (‘swEet’ heart = E-) from London (-LON-) theatre (-GATE) (ELONGATE),
19 Equalised without aid (‘equalised’ without ‘aid’ = equlse = SEQUEL) from one of those following on (SEQUEL),
20 Cotton on to (WISE UP) what’s in Get Smart (WISE UP),
23 Omens (SIGNS) in passing shot lacks pathos (‘passing shot’ lacks ‘pathos’ = ssing = SIGNS).