Across:
8 Toned-down (SUBTLE) bluest (bluest = SUBTLE) dress (= anagram indicator),
9 At the front, novice (at the front ‘novice’ = N-) loses head (h) with jockey (‘horseman’ without ‘h’ = -ORSEMAN) (NORSEMAN) and one of the old raiders (NORSEMAN),
10 Recruits with no cure (‘recruits’ with no ‘cure’ = rits = STIR) for disturbance (STIR),
11 To emulate Monet (paint), for the most part (t) (‘paint’ without ‘t’ = PAIN-), will take your breath away (-KILLER) (PAINKILLER) and will remove a long-suffering ache (PAINKILLER),
12 Emigrant loses it (‘emigrant’ loses ‘it’ = emgran = GERMAN), in a manner of speaking, in Munich (GERMAN),
14 Mascot in (mascot in = MONASTIC) play (= anagram indicator) describes being confined to a cell all day (MONASTIC),
15 Organisation (UN-) finds omission (-EXCEPTION-) by a (-A-) lawyer (-BL-) from Spain (-E) (UNEXCEPTIONABLE) is not much to write home about (UNEXCEPTIONABLE),
18 New (= anagram indicator) bus decor (bus decor = OBSCURED) goes unnoticed (OBSCURED),
20 Shipmates ignore map (‘shipmates’ ignore ‘map’ = shites = THESIS) produced by scholar in final year (THESIS),
22 Type of haircut (TENNIS BALL haircut) for one of those getting knocked about in court (TENNIS BALL),
24 Champion (HERO) what’s covered up by beach erosion (what’s covered up by ‘beach erosion’ = HERO),
25 Put the foot down (DEMANDED), as Guy (man) and Duke! (d) are together – indeed? (‘indeed’ = ‘in deed’ : ‘-MAN-’ + ‘D’ are together in DE-ED) (DEMANDED),
26 Would people lie about this (SETTEE) fix (SET-) picked up by swinger? (-TEE picked up by swinger/golfer) (SETTEE).
Down:
1 Slow type (TURTLE) comes out of his shell every so often (TURTLE),
2 Important person (STAR) with fragment of fascist artefact (fragment of ‘fascist artefact’ = STAR),
3 Sally (RESPONSE) and Buck (= anagram indicator) Spenser (Spenser = RESP-NSE) welcoming Oscar (-O-) (RESPONSE),
4 Opposed (ANTI) to characters in Constantinople (to characters in ‘Constantinople’ = ANTI),
5 Rob (rob = BRO-) Cook (= anagram indicator) and Kenneth (-KEN) (BROKEN) Shatter in the past (‘shatter’ in the past = shattered = BROKEN),
6 It’s about (RE-) getting a number of beers (ales = -AL ES-) at the foreign museum (-TATE museum) (REAL ESTATE) buildings (REAL ESTATE),
7 Duck (duck cotton/canvass = type of MATERIAL) in fish net – presumably that’s a yarn! (fishnet MATERIAL),
13 Most of those in 24 down (most of ‘hats = HAT) after (= positional indicator) resident of Guadalajara (MEXICAN) (MEXICAN HAT) providing protection from The Sun (MEXICAN HAT),
14 Used a remote (used a remote control = MUTED) mansion on summit (‘mansion’ on summit = M-) for possible (= anagram indicator) duet (duet = -UTED) (MUTED),
16 The foreign (the = LE-) workers (men) briefly (n) (‘men’ without ‘n’ = -ME-) in Bonn (Bonn = NOB-N) unsettled (= anagram indicator) (NOBLEMEN) by peers (peers/aristocrats = = NOBLEMEN),
17 It’s common knowledge (it’s OUT) – on top of climb (on top of ‘climb’ = -C-), young woman (-LASS) (OUTCLASS) gets to blow away the competition (OUTCLASS),
19 Jockey (= anagram indicator) rides (rides = RESID-) the last race (the last ‘race’ = -E) (RESIDE) in habit? (‘in habit’ = ‘inhabit’ / live in = RESIDE),
21 Earl is (earl is = ISRAEL) out (= anagram indicator) in the Middle East (ISRAEL),
23 Benefits (AIDS) of removing keel from lakeside (removing ‘keel’ from ‘lakeside’ = asid = AIDS),
24 Send off handsets (‘send’ off ‘handsets’ = hats = HATS) for going over the heads (HATS).