Across:
8 Foreign Office (BUREAU) is often against The Wall (dresser/chest = BUREAU),
9 Oriental (oriental = RELATION) boss (= anagram indicator) has links to La Familia (RELATION),
10 Innocently dismissed Lennon (‘innocently’ dismissed ‘Lennon’ = icty = CITY) in Liverpool, for instance (CITY),
11 Novel (= anagram indicator) in contrast (in contrast = CONSTRAINT) has its own limitation (CONSTRAINT),
12 Each (each = CHA-E) criminal (= anagram indicator) sheltering heartless (heartless/without centre = ‘u’) Persian (‘rug’ without ‘u’ = -RG-) (CHARGE) from The Bill (CHARGE),
14 Did one take more positions than one needed (OVERBOOK) with finished (OVER-) novel? (-BOOK) (OVERBOOK),
15 The Greens are always going on about this (CARBON FOOTPRINT) diamond (CARBON) – it’s a clue for the detective (FOOTPRINT) (CARBON FOOTPRINT),
18 Staff members (INSIDERS) from popular (IN-) writing (from the 3Rs = -R-) teams (teams/sides = -SIDE-S) doing the rounds? (INSIDERS),
20 It’s important (it’s KEY-) to public – address (Public Address = -PA-) department (-D) on the phone (KEYPAD),
22 Fairly (half of) despised (half of ‘despISED’ = -ISED) bookmaker (AUTHOR-) from the start (= position indicator) (AUTHORISED) gave the thumbs up (AUTHORISED),
24 Out of sorts (sad = DAS-) going back (= reversal indicator) to hospital (-H) (DASH) in Rush (rush/hurry = DASH)
25 Someone who knows the shape of things to come (SCULPTOR) makes an impression on one of The Stones (SCULPTOR),
26 The first one (WINNER) to get it out of wire netting (‘get it’ out of ‘wire netting’ = wirenn = WINNER).
Down:
1 Discipline (PUNISH) Press (push = PU-SH) covering Ulster (Northern Ireland = -NI-) (PUNISH),
2 Charge (LEVY) for getting off flyover (‘for’ getting off ‘flyover’ = lyve = LEVY),
3 Take control (MUSCLE IN) with 1,000 (M-) new (= anagram indicator) clues (clues = -USCLE-) that could be popular (IN) (MUSCLE IN),
4 Tracy left Cary Grant (‘Tracy’ left ‘Cary Grant‘ = argn = GRAN) in the old folks home perhaps (GRAN),
5 Fit out (CLOTHE) club (C-) at exotic (= anagram indicator) hotel (hotel = -LOTHE) (CLOTHE),
6 Wander (stray = STRA-Y) across women (-W-) with bloodhounds starting (‘Bloodhounds’ starting = -B-) to bark up the wrong tree (err = -ERR-) (STRAWBERRY) for fruit (STRAWBERRY),
7 Being overtaxed (being over taxed = WORN DOWN), took the gold (won = WO-N) around river (-R-) from half of those in 17 down (half of ‘take down’ = -DOWN) (WORN DOWN),
13 Talk at length (RABBIT) on course (HOLE) (RABBIT HOLE) offering passage from Alice in Wonderland, for one (RABBIT HOLE),
14 Old (O-) Bones (bones) removes heart (removes heart/centre = ‘n’) (‘bones’ without ‘n’ = -BOES) (OBOES) with a number of instruments (OBOES)
16 Make it known (ANNOUNCE) to woman (ANN-) it doesn’t carry much weight (-OUNCE) (ANNOUNCE),
17 Remove from the board (TAKE DOWN), for instance (TAKE), in Northern Ireland? (DOWN) (TAKE DOWN),
19 Sightseer fails to get his (‘sightseer’ fails to get ‘his’ = gtseer = EGRETS) birds (EGRETS),
21 Remedy (ANSWER) is way out? (ANSWER),
23 Certain (SURE) poster from superstore (‘poster’ from ‘superstore’ = suer = SURE),
24 Raise (= reversal indicator) some outspoken ideas (some ‘outspokEN IDeas’ = enid = DINE) to feast on (DINE).