Across:
8 Take the air (STROLL) out of the last of the doughs (last of the 'doughS' = S-) ultimately for wheat (ultimately for 'wheaT' = -T-) bread (-ROLL) (STROLL),
9 Great local (‘great’ locally = SMASHING) craic (craic) overheard (= homophone indicator) (‘craic = ‘crack’ = SMASH-) in (-IN-) Government (-G) (SMASHING),
10 Play notes on the guitar (FRET) picked up (= reverse indicator) in Chesterfield (in ‘chesTERField’ = terf = FRET),
11 Ability to fight off (RESISTANCE) as in secret (as in secret) movement (= anagram indicator) (as in secret = RESISTANCE),
12 Guard (ESCORT) in operative’s Cortina (in ‘operativES CORTina’ = ESCORT),
14 Sets up (= reversal indicator) agent (rep = PER-) from America (-US-) in (-IN-) government (-G) (PERUSING) taking an interest in the classified documents? (PERUSING),
15 Reveal a secret (GIVE THE GAME AWAY) to hand over monopoly? (hand over Monopoly = GIVE THE GAME AWAY),
18 Illustrations (DRAWINGS) in Darwin (Darwin = DRAWIN-) drawn (= anagram indicator), by head of grammar (head of ‘Grammar’ = -G-) school (-S) (DRAWINGS),
20 Hypothesis (THEORY) leads to extremes? The rest is history! (extremes of ‘THE rest is histORY’ = THEORY),
22 You get this after a heavy fall resulting in Flood (STORMWATER) and most of the characters in 1 down (most ‘storms’ = STORM-) going for drink (-WATER) (STORMWATER),
24 Some overambitious revolutionary (= reverse indicator) (some ‘ovERAMbitious’ = eram = MARE) mother of Arabian (mother of Arabian horse = MARE),
25 Is under pressure (STRESSED) serving up (= reverse indicator) sweets, of course (sweets of course = desserts = STRESSED)
26 Haunts (haunts) complex (= anagram indicator) (haunts = SUN HAT) in Panama (Panama SUN HAT).
Down:
1 Charges (STORMS) for short (y) story (story) ('story' without 'y' = STOR-) manuscript (-MS) (STORMS),
2 Characters in Psycho’s trailer (characters in ‘psycHOS Trailer = HOST) produced by entertaining figure (HOST),
3 The foreign (‘the’ foreign/Spanish = EL-) channel (ditch = D-ITCH) covering spirits at The Centre (‘spiRits’ at the centre = -R-) (ELDRITCH) is spooky (ELDRITCH),
4 Enjoys the sun (basks), takes off top (b) (‘basks’ without ‘b’ = ASKS) and poses? (poses a question = ASKS),
5 A skier (a skier) travels (= anagram indicator) (a skier = KAISER) over old German mountains and other bits of land (KAISER),
6 One of those from Ray’s family (-SKATE) is after (= position indicator) going for a song (CHEAP-) (CHEAPSKATE) from Scrooge (CHEAPSKATE),
7 Canada (Canada) nervous (= anagram indicator) (Canada = ANAC-DA) about what’s broadcast (-ON-) (ANACONDA) by a snaky type (ANACONDA snake),
13 Heavily taxed? (OVERWORKED) It’s what those worn down by Labour complain about (OVERWORK-) to journalist (-ED)! (OVERWORKED),
14 Having been produced by bookish type (PAGES) – lead pencil (lead/first letter of Pencil = P-) doesn’t look new (-AGES) (PAGES),
16 One (I-) writing (from the 3Rs = -R-) to judge (rate = -R-ATE) about it (-IT-) (IRRITATE) – is that to try one’s patience? (IRRITATE),
17 Starter of mushroom (starter of ‘Mushroom’ = M-) risotto (risotto) prepared (= anagram indicator) (risotto = -OTORIST) (MOTORIST) with one for the road? (MOTORIST),
19 Just out (NEWEST) on the outskirts of New York forest (outskirts of ‘NEW york forEST’ = NEWEST),
21 Had another look at (REREAD) grenadier spitting out gin (‘grenadier’ spitting out ‘gin’ = reader = REREAD),
23 Make shipshape (TIDY), as admiralty ignores alarm (‘admiralty’ ignores ‘alarm’ = dity = TIDY),
24 Take care (MIND) of lads from Midlands (‘lads’ from ‘Midlands’ = midn = MIND).