Across:
8 White fish (BELUGA) from Belgium (BE-) found in the odd lounge (odd letters of 'LoUnGe' = -LUG-) and top alehouse (top 'Alehouse' = -A) (BELUGA),
9 Formal defence (APOLOGIA) of American (A-) Assistant (-P-A) overseeing igloo (igloo) reconstruction (= anagram indicator) (igloo = -OLOGI-) (APOLOGIA),
10 A consumer of clothing (MOTH) taken in by upsetting (= reversal indicator) outlandish tomfoolery (‘outlandisH TOMfoolery’ = htom = MOTH),
11 Bar traitor (bar traitor), criminal (= anagram indicator) (bar traitor = ARBITRATOR) and judge? (ARBITRATOR),
12 Tin (CAN-) found on a (-A-) land at the centre (‘lANd’ at the centre = -AN) (CANAAN) of a promising piece of real estate (The Promised Land = CANAAN),
14 A Bandon (abandon = RENOUNCE) hermit (loner) heading off (l) (‘loner’ without ‘l’ = oner) back (= reverse indicator) (oner = RENO-) to a French (‘a’ French = -UN-) church (Church of England = -CE) (RENOUNCE),
15 Primitive (UNSOPHISTICATED) organisation (UN-) associated with Cosmopolitan (-SOPHISTICATED) (UNSOPHISTICATED),
18 Sounds like Armagh might do this during Ulster Championship? (PLAY DOWN) Oh, that won’t happen! (PLAY DOWN something),
20 In tears? (CRYING) Caught (C-) with lucky right (‘luckY’ right = -Y-) in boxing venue! (ring = -R-ING) (CRYING),
22 Lay the foundations (INAUGURATE) in old city (-UR-) in Antigua (Antigua) possibly (= anagram indicator) (Antigua = INAUG-AT-) close to consulate (close to ‘consulatE’ = -E) (INAUGURATE),
24 Get wind of (HEAR) sweetheart releasing tweets (‘sweetheart’ releasing ‘tweets’ = hear = HEAR),
25 Keep under control (RESTRAIN) with a fair amount of (half) care (half of ‘caRE’ = RE-) heading for the sun (heading for the ‘Sun’ = -S-) with flying Scotsman (Flying Scotsman = -TRAIN) (RESTRAIN),
26 Purchases don’t include ash (‘purchases’ don’t include ‘ash’ = purces = SPRUCE) – a tree popular at Christmas? (SPRUCE).
Down:
1 Some rebuffed or antagonised (some 'rebufFED OR Antagonised' = FEDORA) by one coming out of millinery (FEDORA),
2 Take stock from tuck shops (take ‘stock’ from ‘tuck shops’ = uhps = PUSH) to market locally (PUSH),
3 A fat cat (SAVANNAH cat) found in Georgia (SAVANNAH),
4 Thorn (BARB) found in banks of balsam herb (found in banks of ‘BAlsam heRB’ = BARB),
5 Attorneys having no say (‘attorneys’ having no ‘say’ = ttorne = ROTTEN) in what’s dishonest (ROTTEN),
6 Presumably, you get this from talking shop (VOCABULARY) with that collective that has a word for everything (VOCABULARY),
7 Is separated, in a way (DIVORCEE), from one who left the match early (DIVORCEE),
13 The trouble-shooting columnists (AGONY AUNTS) getting grief (AGONY) from state (= homophone indicator) workers (‘ants’ = ‘AUNTS’) (AGONY AUNTS’),
14 It’s about (RE-) what’s not right (-SIN) (RESIN) with sticky stuff in various plants and trees (RESIN),
16 At this moment (now) briefly (w) (‘now’ without ‘w’ = NO) more strung out? (LONGER) (NO LONGER) Not any more! (NO LONGER),
17 Become greater (INCREASE) with a sincere (a sincere) shift (= anagram indicator) (a sincere = INCREASE),
19 Comic (jocular) loses the head (j) (‘jocular’ without ‘j’ = OCULAR) – it’s to do with the viewers? (OCULAR),
21 A subtle difference (NUANCE) in answer (-A-) welcomed by Sister (nun = NU-N-) Clare (Clare = -CE) (NUANCE)
23 Most of those closing 13 down (most of those closing ‘agony aunts’ = AUNT) for a family member (AUNT),
24 Meredith has no time (‘Meredith’ has no ‘time’ = redh = HERD) for that type of mentality (HERD mentality).