Across:
8 Brief (d) temporary fashion (fad) (‘fad’ without ‘d’ = FA-) for a gent’s (‘a gents’ = ‘agents’ = -CIA-) lotion – the first (‘Lotion’ the first = -L) (FACIAL) offered by Spa (FACIAL),
9 Most of those (‘t’) opening 15 across (opening of ‘cabinet minister’ = ‘cabinet’ without ‘t’ = CABINET-) with summit speech (summit ‘Speech’ = -S) (CABINETS) protective of China perhaps? (china CABINETS),
10 Took to Twitter (took to twitter like a bird = SANG) consumed by bipartisan grievance (consumed by ‘bipartiSAN Grievance’ = SANG),
11 The Big Dogs (GREAT DANES) in Hamlet (GREAT DANE-), close to Claudius (close/end to ‘claudius’ = -S) (GREAT DANES),
12 Spread it about again (REOPEN) – one per (one per) shift (= anagram indicator) (one per = REOPEN),
14 Disputes (DISCORDS) with detectives (DIs = DIS-) on The Wire (-CORD-) on bender (-S bend) (DISCORDS),
15 Keeps an eye on finance, for one (CABINET MINISTER), for what carpenter put together (CABINET) in the church (MINISTER) (CABINET MINISTER),
18 Political appointee (MINISTER) close to 15 across (close/end to ‘cabinet minister’ = MINISTER),
20 The Queen’s (the queens = ROYALS) produced by those in 1 down (ROYALS in ‘palace’),
22 A gambling system (MARTINGALE) for bird (MARTIN-) generally the first (‘Generally’ the first = -G-) to go on the beer (-ALE) (MARTINGALE),
24 Light at the end of the tunnel (HOPE) in fragment of French opera (in fragment of ‘frencH OPEra’ = HOPE),
25 Got together again (REUNITED) with one (-UNIT-) in Rush (rush/plant = RE-ED) (REUNITED),
26 Tag on (APPEND) a (-A-) tip of pocket (tip of ‘Pocket’ = -P-) writing instrument (-PEN-) and note (music note -D) (APPEND).
Down:
1 Paid (paid) a fair amount (half of) (‘PAid’ half of = PA-) amount for Chantilly (Chantilly Lace = -LACE) (PALACE) chateau (PALACE),
2 Folk (KIN-) legend (‘leg’ end = -G) (KING) from 1 down (KING from ‘palace’),
3 Maria leaves American eagle (‘Maria’ leaves ‘American eagle’ = ecneagle = ELEGANCE) with Grace (grace = ELEGANCE),
4 Part of cul-de-sac reclassified (part of ‘cul-de-sAC REclassified’ = ACRE) as farmland (ACRE),
5 Peter’s out (peters out = ABATES) with a (A-) troop leader (‘Troop’ leader = -T-) in new (= anagram indicator) base? (base = -BA-ES) (ABATES),
6 Endless (o) facts and figures (‘info’ without ‘o’ = INF-) from unreliable (= anagram indicator) asylum (asylum = -AM-USLY) around Oxford (-O-) (INFAMOUSLY) notoriously bad? (INFAMOUSLY),
7 Last (= position indicator) drugs (E+E = -EE) deal with (ATTEND- to) (ATTENDEE) partygoer (ATTENDEE),
13 Old man from Middle East (PHILISTINE) gets hip (hip) replacement (= anagram indicator) (hip = PHI-) – the first (1st = -IST-) in a long queue (line = -L-INE) (PHILISTINE),
14 Show reluctance (DEMUR) to express doubts? (DEMUR),
16 Produced a type of film (ANIMATED) clip (l) of Bambi (‘animal’ without ‘l’ = ANIMA-) by the (the) heartless (h) (‘the’ without ‘h’ = -TE-) director (-D) (ANIMATED)
17 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),
19 United States dismiss audits (‘United States’ dismiss ‘audits’ = nettes = TENETS) as ideology (TENETS),
21 Howling type (LUPINE) of wild (= anagram indicator) line-up (line up = LUPINE),
23 Isolated without lost (‘isolated’ without ‘lost’ = iaed = AIDE) member of staff (AIDE),
24 Build up (HYPE) to part of the McCarthy period (part of the ‘mccartHY PEriod’ = HYPE).