Across:
8 Amidst eleven Etonians (some 'eleVEN ETOnians' = VENETO) taking in Venice (VENETO),
9 In a sorrowful state (MOURNING), as he’s leaving nursing home (‘hes’ leaving ‘nursing home’ = nuringom= MOURNING),
10 Take orders (OBEY) for Hawkeye bootlegs turning up (= reverse indicator) (for ‘hawkeYE BOotlegs’ turning up = yebo = OBEY)
11 Identify (FINGER-) Spike (-NAIL) (FINGERNAIL) is a little nipper that might need polishing? (FINGERNAIL),
12 College (C-) in Haiti (Haiti) staggered (= anagram indicator) (Haiti = TAI -HI) (TAI CHI) by exercise that encourages arty type of go-slow? (TAI CHI martial art),
14 Knock over (FLIP-) material in the studio (paint) – it’s heartless (i) (‘paint’ without ‘I’ = -PANT) (FLIPPANT) and thoughtless (FLIPPANT),
15 Presumably, doesn’t want to join The Guards (RESISTING ARREST) or is that not giving in (RESISTING) to 26 across? (‘arrest’ = ARREST) (RESISTING ARREST),
18 Describes type of recommendations that might not be accepted (ADVISORY) or is Davy (or is Davy) wrong? (= anagram indicator) (or is Davy = ADVISORY),
20 A gent thrown off state ground (‘a gent’ thrown off ‘state ground’ = stroud = TUDORS) leading to a royal house (TUDORS),
22 Incorporate (ASSIMILATE) a (A-) Matisse (Matisse) forgery (= anagram indicator) (Matisse = -SSIM-ATE) about the Italian? (‘the’ Italian = -IL-) (ASSIMILATE),
24 Man of Letters dismisses a monster (‘Man of Letters’ dismisses ‘a monster’ = flet = LEFT) in Split? (LEFT),
25 Outlaw (CRIMINAL) in Mini? Carl (mini carl) Batty (= anagram indicator)! (mini carl = CRIMINAL),
26 Pick up local (pick up ‘locally’ = ARREST) American (A-) charger from the foundation (‘chargeR’ from the foundation = -R-) to recharge one’s batteries (-REST) (ARREST).
Down:
1 No Lent in East Berlin (no 'Lent' in 'East Berlin' = easbri = SERBIA) or in Central Europe (SERBIA),
2 Challenge (DENY) what’s concealed by Dresden youths (what’s concealed by ‘dresDEN Youths’ = DENY),
3 Falling out (CONFLICT) of bed (cot = CO-T) getting to grips with new (-N-) local film (flick), for the most part (k) (‘flick’ without ‘k’ = -FLIC-) (CONFLICT),
4 Those characters embraced by Jeanne Moreau (those characters embraced by ‘jeanNE MOreau’ = nemo) going all the way back (= reverse indicator) (nemo = OMEN) in The Black Cat? (OMEN),
5 The bones (HUMERI) of philosopher- (philosopher David HUME-) -king in Ireland (‘king’ in Ireland = rí = -RI) (HUMERI),
6 Run-of-the-mill (UNINSPIRED) organisation (United Nations organisation = UN-) is stirred to action (-INSPIRED) (UNINSPIRED),
7 Canniest (canniest) boss (= anagram indicator) (canniest = ANCIENTS) of older people (ANCIENTS),
13 Censures (CRITICISMS) judge (CRITIC-) from Ireland (-I-) getting the message whichever way you look at it (short message service = -SMS) (CRITICISMS),
14 Strange (FUNNY) leader of Florida (leader of ‘Florida’ = F-) – a French- (‘a’ French = -UN-) -American state (New York = -NY) (FUNNY),
16 Consumers (END USERS) wind-up (END) those taking drugs (USERS) (END USERS),
17 Where you’ll find caseworkers (AT THE BAR) in a (A-) race (Isle of Man Tourist Trophy = TT race = -T T-) to get rehab (rehab) treatment (= anagram indicator) (rehab = -HE BAR) (AT THE BAR),
19 They’re all revolutionaries (= reverse all indicator) starting trouble (starting ‘Trouble’ = -T) with Roman emperor (Nero = -OR-EN-) over island (-I-) rebelling (ORIENT) in the East (ORIENT),
21 Decline (REFUSE) to set (= anagram indicator) free (free = REF-E) around America (-US-) (REFUSE),
23 Up to the task (ABLE)? Even Ray Bolger! (even letters of ‘rAy BoLgEr = ABLE),
24 Master (LORD) of what’s invested in commercial ordering (invested in ‘commerciaL ORDering = LORD).