Across:
8 Put away (put away/lock away = COMMIT), as it causes readers to pause (comma) – for the most part (a) (‘comma’ without ‘a’ = COMM-) it’s (its) unfinished (s) (‘its’ without ‘s’ = -IT) (COMMIT),
9 Neapolitan (Neapolitan SAUCE-) relative (-PA-) is not the first (‘Not’ the first = -N) (SAUCEPAN) on the range (SAUCEPAN),
10 Co-star dropped by Sportscast (‘co-star’ dropped by ‘Sportscast’ = psst = PSST) is the sort of attention grabber that not everyone will catch (PSST),
11 Revolutionary (RED) father (parish priest = -PP-) among the titled few (PE-ERS) (RED PEPPERS) with the colourful Bells (colourful bell peppers = RED PEPPERS),
12 Sister (NUN-) from island (-I-) taken in by company (Co = -C-O) (NUNCIO) ambassador (NUNCIO),
14 Weekend (‘weeK’ end = -K-) bar (BAN-) opens (= positional indicator) to acknowledge (-NOTE) (BANKNOTE) Bill from America (BANKNOTE),
15 Remembers (COMMITS TO MEMORY) 8 across (‘commit’ = COMMIT-) at unfinished (p) station (‘stop’ without ‘p’ = -S TO) with 20 across (‘memory’ = MEMORY) (COMMITS TO MEMORY),
18 Junkie (USER-) from party (Sinn Féin = -S F-) gets a couple of pills (-EE) (USER’S FEE) in payment for renting opium den presumably (USER’S FEE),
20 More (more = -EMOR-) confusion (= anagram indicator) in my (M-Y) (MEMORY) powers of recollection (MEMORY),
22 For example, takes The Telegraph (SUBSCRIBER takes The Telegraph) editors (SUBS-) onto boat (-RIB-) in Clare (C-E-) river (-R) (SUBSCRIBER),
24 Borders on moral turpitude (borders on ‘MOral turpituDE’ = MODE) in Vogue (in vogue/fashion = MODE),
25 It’s not cheeky (REVERENT) to have a high opinion of (REVERE-) good books (New Testament = -NT) (REVERENT),
26 Other half (SPOUSE) of Trim (t) location (‘spot’ without ‘t’ = SPO-) for most of those in 4 down (most of ‘used’ = -USE) (SPOUSE).
Down:
1 Sample of catch on shuttle (sample of ‘catcH ON SHUttle’ = HONSHU) in Japanese waters (HONSHU island),
2 Forget (OMIT) extract from sanctimonious (extract from ‘sancTIMOnious’ = timo) review (= reversal indicator) (timo = OMIT),
3 Embark on a journey (START OUT) with sailor (-TAR-) consumed by drink (stout = S- T OUT) (START OUT),
4 Employed (USED) retired (= reversal indicator) characters from Trades Union (characters from ‘TraDES Union’ = desu = USED),
5 Listen to (TUNE IN) lieutenant dismissing tale (‘lieutenant’ dismissing ‘tale’ = iuennt = TUNE IN),
6 Relative (MUM) is behind (= positional indicator) paying maintenance (KEEPING) (KEEPING MUM) and saying nothing (KEEPING MUM),
7 In retrospect (= reversal indicator), made tracks (ran = NAR-) with artist (-RA-) and tenor (-T-) or (-OR) (NARRATOR) with one of those doing voice-over (NARRATOR),
13 Squeezed (COMPRESSED) The Media (-PRESS-) into Medoc (Medoc = COM-ED) complex (= anagram indicator) (COMPRESSED),
14 Get into hot water perhaps (BATHE) with 23 down (‘bath’ = BATH-) at the end of the game (end of the ‘gamE’ = -E) (BATHE),
16 Hides (OBSCURES) half of Jacob’s (half of ‘JacOBS’ = OBS-) smokes (-CURES) (OBSCURES),
17 Don’t forget (MEMORISE) viral phenomenon (MEM-E) about old (-O-) teacher (sir = -RIS-) retiring (= reversal indicator) (MEMORISE),
19 Let slip (FORGET) this is the antithesis of 17 down (FORGET is the antithesis of ‘memorise’),
21 Vegetable (RADISH) in unfinished (w), uncooked (‘raw’ without ‘w’ = RA-) Sushi, for instance (-DISH) (RADISH),
23 No cures in Bucharest (no ‘cures’ in ‘Bucharest’ = bhat = BATH) for someone wanting to get clean (BATH),
24 Flash (MOON) of the extremes of Monty Python (the extremes of ‘MOnty PythON’ = MOON).