Across:
1 Provide cover for (ASSURE) foolish type (ASS-) heading off (c) to smoke (‘cure’ without ‘c’ = -URE) (ASSURE),
4 Off head (h) on drugs (‘hash’ without ‘h’ = ASH-) holding the drinks (-TRAYS) (ASHTRAYS) the smokers ordered (ASHTRAYS),
9 Mouthy types (PANELS) can be as thick as the wall? (PANELS),
10 Jasmine (VINE) in the book (LEAF) (VINE LEAF) is used by gastronomic type to wrap things up (VINE LEAF),
12 Rub shoulders (ASSOCIATE) of teammate (ASSOCIATE),
13 A French feminine type (French ‘a’ = une = UN-E) entertains 150 (Roman 150 = -CL-) (UNCLE) from the family (UNCLE),
14 Mafia leader (Don = DO N-) got (got) away at first (g) (‘got’ without ‘g’ = -OT) with trouble (DISTURB) (DO NOT DISTURB) in the hotel – it’s a sign no will lose sleep over this (DO NOT DISTURB),
18 Open the drinks (DO THE HONOURS) party (DO) for most of them (most of ‘them’ = THE) mentioned in Dispatches (HONOURS) (DO THE HONOURS),
21 Charlie’s missing his (‘Charlies’ missing ‘his’ = carle = CLARE) county (CLARE),
22 Take another look (RE-EXAMINE) about (RE-) for note (music note -E-) to Maxine (Maxine = -XAMINE) Rock (= anagram indicator) (RE-EXAMINE),
24 Not even (ODD-) one (-I-) connection (-TIE-) to society (-S) (ODDITIES) with a number of idiosyncrasies (ODDITIES),
25 No permit in Maritime Alps (no ‘permit’ in ‘Maritime Alps’ = aimals = SALAMI) for cured sausage (SALAMI),
26 The nerve (TEMERITY) of station (RTE) losing head (R) (‘RTE’ losing ‘r’ = TE-) with quality (-MERIT-) at the end of the day (end of the ‘day’ = -Y) (TEMERITY),
27 Builder (= anagram indicator) learnt (learnt = RENTAL) from temporary accommodation (RENTAL).
Down:
1 Shows one’s appreciation (APPLAUDS) to a (A-) minister (parish priest = -PP-) at prayer service (-LAUDS) (APPLAUDS),
2 Envy (SIN- one of the deadly sins) relative (-SON-) carried by horse (GG = -G-G) (SINGSONG) popular with those doing the numbers (SINGSONG),
3 Some software licence (some ‘software licence’ = RELIC) for those visiting museum (RELIC),
5 Do two of these keep a woman balanced (STILETTO HEEL) for when she puts her foot down? (STILETTO HEEL),
6 Bake (= anagram indicator) burnt here (burnt here = THE BURREN) and in 21 across (THE BURREN in ‘Clare’),
7 Company (AGENCY) has time (AGE-) to rebuild (= anagram indicator) New York City (NYC = -NCY) (AGENCY),
8 Not (= anagram indicator) sure (sure = SU-ER) about party (Fianna Fáil = -FF-) (SUFFER) to put up with (SUFFER),
11 Looks after flock (PARISH PRIEST) in community (PARISH) with ripest (ripest = PRIEST) bananas (= anagram indicator) (PARISH PRIEST),
15 Starter of tender (starter of ‘tender’ = T-) pig (sow = WO S-) served up (= reversal indicator) by diner (-EATER) (TWO-SEATER) for couple at drive-in (TWO-SEATER),
16 Julian (Julian = JU-ILAN-) Cook (= anagram indicator) holds key (music key -B-) to chalet at foundation (“chalet” at foundation = -T) (JUBILANT) on top of the world (JUBILANT),
17 Devised (= anagram indicator) epic sale? (epic sale = ESPECIAL) That’s unusual! (unusual = ESPECIAL),
19 Demonstrate (ACT OUT) to Bill (ACT) on holiday (OUT) (ACT OUT),
20 Campaigned (RAN-) for party (-DO-) leader managing (leader ‘managing’ = -M) (RANDOM) something uncoordinated (RANDOM),
23 Some characters in Ottawa keeping (some characters in ‘Ottawa keeping’ = AWAKE) up (AWAKE).