Across:
8 Juvenile (lad = LA-D-) paper’s (ID papers = -I-D-) lead: “Advice (lead ‘advice’ = -A) (LA-DI-DA) can be pretentious, in a manner of speaking” (LA-DI-DA),
9 It’s under control (OBEDIENT) in old (O-) part of the allotment (-BED-) on Irish domain (Irish domain = i.e. = -IE-) by nectarine trees, for starters (‘nectarine trees’ for starters = -NT) (OBEDIENT),
10 Extract of Balzac ideology (extract of ‘Balzac ideology’ = ACID) can be corrosive (ACID),
11 Provide guns (ARM-) to mature (-AGED-) gangster (-DON) (ARMAGEDDON) for final conflict (ARMAGEDDON),
12 Most of (e) the investigation (“case” without “e” = CAS-) in (-IN-) Ring (-O) (CASINO) is looking to recruit dealers perhaps (CASINO),
14 Withdrawn (RETICENT) by secretive type (RETICENT),
15 Describes old conductor taking time off (A BUSMAN’S HOLIDAY) to take the coach to Kerry for the holidays, for example (A BUSMAN’S HOLIDAY),
18 Cats (PERSIANS) in Spain (Spain = P-IANS) roaming (= anagram indicator) around summits of Estremadura, Rioja (summits of ‘Estremadura Rioja’ = -ER-) and far side of Pyrenees (far side of Pyrenees = -S) (PERSIANS),
20 Square (EVEN UP) flat (EVEN) for party (DUP) leader gone astray (d) (‘dup’ without ‘d’ = UP) (EVEN UP),
22 Sick and tired (CHEESED OFF) of what’s said to the photographers (CHEESE-) and director (-D) not getting on (getting OFF) (CHEESED OFF),
24 Colourful type (FAWN) from the fringes of Father Brown (the fringes of ‘Father Brown’ = FAWN),
25 Mason puts down (BLOCK-) a fair amount of (half of) the damage (half of the ‘damage’ = -AGE) (BLOCKAGE) to the logjam (BLOCKAGE),
26 Had another look at (REREAD) grenadier spitting out gin (‘grenadier’ spitting out ‘gin’ reader = REREAD).
Down:
1 Spies (-CIA) following (= positional indicator) Swift (fast) briefly (‘fast’ without ‘t’ = FAS-) (FASCIA) for the panel in the Saloon (dashboard in car = FASCIA board),
2 View (MIND) of both sides of the Mississippi Sound (both sides of the ‘Mississippi Sound’ = MIND),
3 A place (home) in the Spanish sun, perhaps (a place/home = CASA-), by river synonymous with Shakespeare (Stratford-upon-Avon = river Avon = -NOVA) set up (= reversal indicator) (CASANOVA) by lover boy (CASANOVA),
4 For one, among schoolchildren (for one, Among School Children = Yeats’ POEM) in Byzantium, for example (Yeats’ POEM Byzantium),
5 Made (= anagram indicator) the wig (the wig = WEIGHT) for one of The Stones, for example (stone WEIGHT),
6 Five (V-) engineers (= anagram indicator) invited (invited = -IND-TIVE) around – one (-I-) hundred (-C-) (VINDICTIVE) might be out for revenge (VINDICTIVE),
7 What definitely affects the retirement plan (INSOMNIA) will keep you up all night (INSOMNIA),
13 Don’t take no for an answer (INSIST-) from English (-E-) novice initially (‘novice’ initially = -N-), one of the Clares (-CE) (INSISTENCE), in great demand (INSISTENCE),
14 Cunning plans (RUSES) to train (= anagram indicator) users (users = RUSES),
16 Dance (B- -ALL) around noble (peer) initially off (p) (‘peer’ without ‘p’ = -EER) his head (‘his’ head = H-) (BEER HALL) in foreign drinking establishment (BEER HALL),
17 Start shooting (OPEN FIRE) with 23 down (‘open’ = OPEN) and 24 down (‘fire’ = FIRE) (OPEN FIRE),
19 Nears a (nears a = ARENAS) settlement (= anagram indicator) with The Rings (ARENAS),
21 Women (-W-) following (= positional indicator) a foreign (a = UN-) music (-RAP music) (UNWRAP) similar to 23 down (‘open’ similar to UNWRAP),
23 Some workshop encapsulated (some ‘workshop encapsulated’ = OPEN) what it means to be accessible to everyone (OPEN),
24 The bank’s financial centre (banks ‘financial centre’ = FIRE) sets off alarm bells (FIRE).