Across:
8 Party (DO-) for half of those in 7 down (half of ‘MAINtain’ = -MAIN) (DOMAIN) from estate (DOMAIN),
9 Croatian (Croatian) novel (= anagram indicator) (Croatian = RAINCOAT) is perfect for that shower (RAINCOAT),
10 They get drunk (ALES) in the extremes of receding (= reverse indicator) Seward Peninsula (the extremes of receding ‘SEward PeninsuLA’ = sela = ALES),
11 Restrictions (CLAMPDOWNS) for Presses (CLAMP-S) across county up north (-DOWN-) (CLAMPDOWNS),
12 Special (= anagram indicator) cheer (cheer = RE-ECH-) for duck (-O) (RE-ECHO) – give me that again! (RE-ECHO),
14 He paints (he paints) swing (= anagram indicator) (he paints = THESPIAN) working in the cherry orchard (in Anton Chekhov’s The Cherry Orchard = THESPIAN),
15 Tenor (T-) managed (-RAN-) Dollar ($ = -S-), Genesis (-FORMATION-) and One Direction (South = -S) (TRANSFORMATIONS) with some changes (TRANSFORMATIONS),
18 No end to ingredients (no ‘end’ to ‘ingredients’ = igrients = IGNITERS) lighting up the ovens (IGNITERS),
20 Revolting (= reverse indicator) retweet (RT = T-R) about more (more = -REMO-) rubbish (= anagram indicator) (TREMOR) comes as a shock (TREMOR),
22 Raises (= reverse indicator) aquatic mammal (otter = -RETTO) from set (gel = -LEG-) for the French (‘the’ French = la = -AL=) (ALLEGRETTO) movement (ALLEGRETTO),
24 Sue getting out of wet suit (‘Sue’ getting out of ‘wet suit’ = wtit = TWIT) is not very clever (TWIT),
25 Article (an = A-N) about the (-THE-) Ulster (Northern Ireland = -NI-) Association (-A-) (ATHENIAN) – the one conceived in Greece (ATHENIAN),
26 Recalling (= reverse indicator) taunt (sneer = -REENS) by great (G-) (GREENS) politicians (GREENS).
Down:
1 Officer (CO-) left (-L-) to tell tale (-LIE) (COLLIE) to associate of shepherd (COLLIE),
2 Some grasp at straws (some ‘graSP AT straws’ = spat) upsetting (= reverse indicator) (spat = TAPS) those supplying water in the kitchen (TAPS),
3 Cheap imitation (KNOCK-OFF) in Mayo (KNOCK) isn’t working (OFF) (KNOCK-OFF),
4 Operatic song (ARIA) from familiar film is cut (from ‘familiar’ ‘film’ is cut/without ‘film’ = aiar = ARIA),
5 Spot (PIMPLE) foreign politician (-MP-) ensconced in stately home (pile = PI-LE) (PIMPLE),
6 A (A-) cold (-C-) place (-PL-) taken in by dandy (Dandy comic = -COM-IC-) and Oriental (East = -E) (ACCOMPLICE) partner in crime (ACCOMPLICE),
7 Service (MAINTAIN) ain’t (aint = -AINT-) available in American (Maine) State (= homophone indicator) (‘Maine’ = ‘main’ = MA-IN) (MAINTAIN),
13 Examined the pros and cons (CONSIDERED) of fraud (CON-) squad (-SIDE-) meeting colourful type (-RED) (CONSIDERED),
14 Turns up (= reversal indicator) group (set = TE-S) holds onto address (Mr = -RM-) (TERMS) – it comes with conditions (TERMS and conditions),
16 Police (REGULATE) order? (REGULATE),
17 In spite of the fact that (ALTHOUGH) Australian (A-) gets time (-T-) for starting hullaballoo (starting ‘Hullaballoo’ = -H-) in lake in Ireland (lough = -L-OUGH) (ALTHOUGH),
19 Listen secretly (EARWIG), for example (e.g. = E-G), around American (-A-) leaders retweeting wrong information (leaders ‘Retweeting Wrong Information’ = -RWI-) (EARWIG),
21 In order to lose Rod (‘in order to’ lose ‘Rod’ = inreto = ORIENT) find one’s bearings (ORIENT),
23 Colourful types (TANS) of fringes on table napkins (fringes on ‘TAble napkiNS’ = TANS),
24 Bound (TIED) to change (= anagram indicator) diet (diet = TIED).