Across:
8 Crafty type (art = TRA-) retires (= reversal indicator) from Russian body (Duma) – losing a leader (d) (‘Duma’ losing ‘d’ = -UMA) (TRAUMA) comes as a shock (TRAUMA),
9 The lands (the lands = SHETLAND) wasted (= anagram indicator) in Scottish island (SHETLAND),
10 Plug (CORK) for bank’s computer network (banks ‘computer network’ = CORK),
11 Monitored a (monitored a = MODERATION) play (= anagram indicator) with restraint (MODERATION),
12 Old European (THEBAN) prohibition restricting the players switching codes in past (THE BAN),
14 Upsets (AILMENTS) salt mine (salt mine = AILMENTS) engineer (= anagram indicator),
15 9 across (SHETLAND) and 26 across (ISLAND) from small (-S) (SHETLAND ISLANDS) Archipelago up north (SHETLAND ISLANDS),
18 Took a few turns coming down the hill (SLALOMED) with distressed (= anagram indicator) damsel (damsel = SLA-MED) carrying half the load (half the ‘load’ = -LO-) (SLALOMED),
20 Hide (LIE LOW) piece of fiction (LIE) – it’s despicable (LOW) (LIE LOW),
22 Frank (OPEN) Spring (SEASON) (OPEN SEASON) is killing time on the estate (OPEN SEASON on estate = hunting time),
24 Have steam coming out of one’s ears (RAGE) at the end of 6 down (‘all the rage’ = RAGE),
25 A (A-) judge from the past (Resident Magistrate = -RM-) takes over the meeting (the chair = -CHAIR) (ARMCHAIR) – it’s handy when one is sitting (ARMCHAIR),
26 For those living off the country perhaps (ISLAND) with one of those in 3 down (one in ‘Tasmania’ = ISLAND).
Down:
1 Is it a badge of honour (BROOCH) for church (-CH) starting (= positional indicator) witchcraft? (witch craft = broom) Mostly! (m) (‘broom’ without ‘m’ = BROO-) (BROOCH),
2 No trade in Turk’s Head (no ‘trade’ in ‘Turks Head’ = uksh = HUSK) or The Pod (pod/shell = HUSK),
3 Aims at an (aims at an = TASMANIA) adaptation (= anagram indicator) in part of Australia (TASMANIA),
4 Took advantage of (USED) some gregarious educationalists (some ‘gregarious educationalists’ = USED),
5 Aura coming out of tea parlour (‘aura’ coming out of ‘tea parlour’ = teprlo = PETROL) in Beetlejuice? (beetle car juice = PETROL),
6 Every ounce of anger (ALL THE RAGE) in Vogue (in vogue = ALL THE RAGE),
7 Started to open (UNBOLTED) a foreign (a = UN-) bar (-BOLT-) with writer (-ED) (UNBOLTED),
13 Perfect place to grab a Magnum perhaps (grab a magnum/wine bottle by BOTTLE NECK) – those travelling by car might want to avoid it (BOTTLENECK),
14 Went on to say (ADDED) Reg left degraded (‘Reg’ left ‘degraded’ = ADDED),
16 Serve (help) endless (p) (‘help’ without ‘p’ = HEL-) Ibérico – firstly (‘Ibérico’ firstly = -I-) with wine (-PORT) (HELIPORT) and on the house for highflyers (HELIPORT),
17 Sidney (S-ID) admits pressure (-P-) to extend credit (-LEND-) (SPLENDID) outstanding (SPLENDID),
19 Relative (MA-) from Copenhagen (Dane = -ENAD) upsets (= reversal indicator) (MAENAD) wild woman from Greece (MAENAD),
21 Those in the body (ORGANS) of horses (breed of horses = Morgans) missing the first (m) (‘Morgans’ without ‘M’ = ORGANS),
23 Certain (SURE) limits to surgical procedure (limits to ‘surgical procedure’ = SURE),
24 Responsibility (ROLE) of the state (= homophone indicator) register for electoral purposes (electoral “roll” = “ROLE”).