Across:
8 Deliver coup de grâce (FINISH) at home (-IN-) trapped by shark (fish = FI-SH) (FINISH),
9 Lounged around (LOITERED) endlessly (w) depressed (‘low’ without ‘w’ = LO-) having to re-edit (re edit) novel (= anagram indicator) (re edit = -ITERED) (LOITERED),
10 Poses a question (ASKS) – what are the Coopers capable of (coopers make barrels/casks) starting off? (c) (‘casks’ without ‘c’ = ASKS),
11 The latest information (news) mostly (s) (‘news’ without ‘s’ = NEW) on neighbour (ENGLAND) (NEW ENGLAND) in America (NEW ENGLAND),
12 Take a shine to (POLISH) one of the buffs (POLISH),
14 Work as a keyholder (gaoler = IMPRISON) in this lock-up and leave? (IMPRISON).
15 Chart (GRAPH-) Third Reich (third ‘reIch’ = -I-) from first of the camps (first of the ‘Camps’ = -C) to architect (DESIGNER) (GRAPHIC DESIGNER) responsible for the visual impact (GRAPHIC DESIGNER),
18 Croaky (‘hoarse’ = ‘horse’ = HORSE-) on the radio (= homophone indicator) and on local television (-BOX) (HORSEBOX) in the trailer for Black Beauty (HORSEBOX),
20 Literary agent drops elegant (‘literary agent’ drops ‘elegant’ = itrary = RARITY) collector’s item (RARITY),
22 Friends (mate) lose the head (‘mates’ lose the head = ates) going back over (= reversal indicator) (ates = SET A) account (RECORD) (SET A RECORD) to establish optimum time of victory (SET A RECORD),
24 Ill-advised dismissing devils (‘ill-advised’ dismissing ‘devils’ = ilad = LAID) with put down (LAID),
25 Knocks the stuffing out of (DEFLATES) fat Leeds (fat Leeds) criminal (= anagram indicator) (fat Leeds = DEFLATES),
26 Make use of (EMPLOY) foreign (= anagram indicator) mole (mole = EM-LO-) over pressure (-P-) from Yard (-Y) (EMPLOY).
Down:
1 Detailed (t) formal order (formal order/decree = ‘fiat’ without ‘t’ = FIA-) for Glaswegian (Scot) doesn’t end (t) (‘Scot’ without ‘t’ = -SCO) (FIASCO) in disaster (FIASCO),
2 Helps out (AIDS) hero from Rhodesia (‘hero’ from ‘Rhodesia’ = dsia = AIDS),
3 Old ruler (SHA-H-) imbibed newly opened (‘newly’ opened = -N-) grand (-G-), first-class (AI) (SHANGHAI) port in China (SHANGHAI),
4 Reduce speed (SLOW) on both sides of sleepy hollow (on both sides of ‘SLeepy hollOW’ = SLOW),
5 Torn from unsporting (‘torn’ from ‘unsporting’ = unspig = SIGN UP) register (SIGN UP),
6 A sound reminder perhaps (BELL RINGER) of leaderless (h) underworld (‘hell’ without ‘h’ = -ELL) gang (RING-) in Belgium (BE = B- -E-) at the end of war (at the end of ‘waR’ = -R) (BELL RINGER),
7 Smitten (BE IN LOVE) by empty (n) African country? (Benin = ‘beNin’ without ‘n’= BE IN) To those in Wimbledon it means nothing! (LOVE means nothing to the tennis players in Wimbledon) (BE IN LOVE),
13 Devil (IMP-) provides a (-A-) top service (top ‘Service’ = -S-) when it’s pitch-black (sable = -SABLE) (IMPASSABLE) with no way through (IMPASSABLE),
14 Laid off in Dixieland (‘laid’ off in ‘Dixieland’ = ixend = INDEX) – that’s one for the books (INDEX),
16 Old (-O-) writer (-PEN-) consumed by uplifting (= reversal indicator) book (book) on the radio (= homophone indicator) (‘book’ = ‘buck’ = deer = RE-ED) (REOPENED) resumed business (REOPENED),
17 A fair amount of (half of) the study (half of ‘REad’ = RE-) by theologian (Doctor of Divinity = -DD-) in shelter (SH-ED) (SHREDDED) is ripped to pieces (SHREDDED),
19 Bit of fresh air (BREATH) in Bath? (Bath = BA-TH) That’s about (-RE-) all there is in that place! (BREATH),
21 Man of the cloth (TAILOR) showing off (= anagram indicator) Rialto (Rialto = TAILOR),
23 Remove from office (OUST) piece of spurious technology (piece of ‘spuriOUS Technology’ = OUST),
24 Mouthy types (LIPS) of headers thrown out of dealerships (‘headers’ thrown out of ‘dealerships’ = lips = LIPS).