Across:
8 Staggers (staggers= trips) back (= reversal indicator) (trips = SPIR-T) around island (-I-) (SPIRIT) from the bar (SPIRIT),
9 Makes up (= anagram indicator) invoice (invoice = EVIC-ION) over time (-T-) (EVICTION) for removal of the house’s contents (EVICTION),
10 Mentor’s son leaves (‘mentors’ ‘son’ leaves/without ‘son’ = metr = TERM) for an academic period (TERM),
11 Finishes off (ERADICATES) arcade site (arcade site = ERADICATES) complex (= anagram indicator),
12 A selection (CHOICE) from Trim (trim/cut = ‘r’) group of singers (‘choir’ without ‘r’ = CHOI-) goes to church (Church of England = -CE) (CHOICE),
14 Sportingly, recovers (PEGS BACK) from stick (PEG-) and initial savagery (initial ‘Savagery’ = -S) with support (BACK) (PEGS BACK),
15 Those in 24 down (‘wine’ = WINE-) found on the beach (sand = -S AND) with 8 across (‘spirit’ = SPIRIT-) and endless (end ‘lesS’ = -S) (WINES AND SPIRITS) types that are drunk (WINES AND SPIRITS),
18 To start off (INITIATE), one (I-) fool (-NIT-) got single (-I-) and wolfed it down (-ATE) (INITIATE),
20 Reading (R-) old (-O-) review (= reversal indicator) cut to pieces (slay = -YALS) (ROYALS) by that lot from The Palace (ROYALS),
22 Religious belief (PROFESSION) in vocation (PROFESSION),
24 Polish (polish/rub = WIPE) strike (strike/hit = swipe) has no leader (s) (‘swipe’ without ‘s’ = WIPE),
25 Essential part of the whole (INTEGRAL) Tangier (Tangier) novel (= anagram indicator) (Tangier = INTEGRA-) is lost (-L) (INTEGRAL),
26 Campaigned (RAN-) for party (-DO-) leader managing (leader ‘Managing’ = -M) (RANDOM) something uncoordinated (RANDOM).
Down:
1 Address (SPEECH) most of the drugs (most of the ‘speed’ = SPEE-) coming from Switzerland (-CH) (SPEECH),
2 Downs first (‘Downs’ first = D-) drink (-RUM) (DRUM) from cask (DRUM),
3 Separatist movement (ETA = ET -A) around revolutionary (= anagram indicator) Crete (Crete = CETER-) (ETCETERA) and the rest (ETCETERA),
4 Sample of ultimate figs (sample of ‘ultimATE Figs’ = atef) served up (= reversal indicator) (atef = FETA) with cheese (FETA),
5 Managing to see (sighting) report (= homophone indicator) (‘sighting’ = ‘CITING’) by referencing a witness perhaps (CITING),
6 Flips over (= reversal indicator) defects figuratively (‘warts and all’ = warts = STRAW-) growing on a vine (-BERRY) (STRAWBERRY) with soft red fruit (STRAWBERRY),
7 When you lose energy (POWER CUT), expect blackouts with this (POWER CUT),
13 Put a name on (IDENTIFIED) one of those singled out (IDENTIFIED),
14 Opens a dark room (opens ‘A Dark Room’ = -ADR-) in gym (PE = P-E) (PADRE) or in a religious building in the services industry (army) (PADRE),
16 Unaware (IGNORANT), Italian gent (signor) lost the head (s) (‘signor’ without ‘s’ = IGNOR-) with worker (-ANT) (IGNORANT)
17 Mate’s (mates = PARTNERS) parents (parents = PARTNE-S) working (= anagram indicator) around river (-R-) (PARTNERS),
19 It’s farcical (ABSURD) to drive (Dr = -RD) the first bus (first ‘Bus’ = -B-) in America (USA = A-SU-) going all the way back (= reversal indicator) (ABSURD),
21 Kitty (pot) and Buddy (pal) setting up (= reversal indicator) (pot = -TOP + pal = LAP-) (LAPTOP) computer (LAPTOP),
23 No introduction (a) to passage (‘aisle’ without ‘a’ = ISLE) – the setting for The Lighthouse (ISLE),
24 Wild jasmine borders (‘WIld jasmiNE’ borders = WINE) in Bordeaux (WINE).