Across:
8 Charlie (C-) Buck (dollar) needs no introduction (d) (‘dollar’ without ‘d’ = -OLLAR) (COLLAR) to Van Dyke, for one? (Van Dyke is a COLLAR),
9 Proof (EVIDENCE) from Germany (Germany domain = .de = -DE-) divides suspicious (= anagram indicator) Venice (Venice = EVI-NCE) (EVIDENCE),
10 Sample of bootleg demo (sample of ‘bootleg demo’ = egde = EDGE) reviewed (= reversal indicator) (egde = EDGE) by lippy type (lip/rim = EDGE),
11 Renaissance guy perhaps (Renaissance man = MAN OF PARTS) – playing all the characters in Shakespeare’s plays, for instance (MAN OF PARTS),
12 Caddie to finish (‘caddie’ to finish = E-) reading (from the 3Rs = -R-) tirade (-RANT) (ERRANT) wandering off course (ERRANT),
14 Gathers together (COLLECTS) in college (C-) setting up (= reversal indicator) part of the orchestra (cello = -OLLEC-) with tenor (-T-) from school (-S) (COLLECTS),
15 Construct a case (COLLECT EVIDENCE) for most of those in 14 across (most of ‘collects’ = COLLECT) and 9 across (‘evidence’ = EVIDENCE) (COLLECT EVIDENCE),
18 Thistle (thistle = LI-HTEST) developed (= anagram indicator) around Gulf (-G-) (LIGHTEST) is the least significant (LIGHTEST),
20 Made an intervention to put Bill away? (made an intervention to put Bill/act of parliament away = VETOED) That’s shot down! (VETOED),
22 Reverberations (VIBRATIONS) from foreign (= anagram indicator) visitor ban (visitor ban = VIBRATIONS),
24 No sense in messenger (no ‘sense’ in ‘messenger’ = mger = GERM) offering the start of an idea (GERM of an idea),
25 One of the offspring (DAUGHTER) produced (= anagram indicator) The Guard (The Guard = DAUGHTER),
26 Reserves (coffers) losing the head (c) (‘coffers’ without ‘c’ = OFFERS) with approaches from other clubs, for instance (OFFERS).
Down:
1 Drew on (drew on = WONDER) career (= anagram indicator) with Marvel (WONDER),
2 Women left unwelcome (‘women’ left ‘unwelcome’ = uelc = CLUE) hint (CLUE),
3 A (A-) place in Italy for the locals (-ROMA-) – it (it = -TI-) is around (= reverse indicator) Calabrian capital (‘Calabrian’ capital = -C) (AROMATIC) with a fragrant disposition (AROMATIC),
4 Characters alongside a nuisance (characters ‘alongside a nuisance’ = DEAN) from college (DEAN),
5 Infamously dismisses Mayo (‘infamously’ dismisses ‘mayo’ = infusl = SINFUL) as godless (SINFUL),
6 Degradation (DEBASEMENT) in the same way (-AS-) English (-E-) workers (-MEN-) can be found in arrears (arrears = debt = D-EBT) (DEBASEMENT),
7 Rooted to the spot (-STATIC) after (= positional indicator) church (Church of England = CE = EC-) backing (= reversal indicator) (ECSTATIC) for seventh heaven? (ECSTATIC),
13 Every ounce of anger (ALL THE RAGE) in Vogue (in vogue = ALL THE RAGE),
14 Remove snow from crow’s nest (remove ‘snow’ from ‘crows nest’ = crest = CREST) on top of the mountain (CREST),
16 Gloria in (Gloria in = ORIGINAL) dress? (= anagram indicator) That’s a first! (ORIGINAL),
17 Popular (IN-) victory (-V-) with a (-A-) short (e) racket (‘noise’ without ‘ e’ = nois) brings up (= reversal indicator) (nois = -SION) (INVASION) offensive attack that’s crosses the line (INVASION),
19 The property of the gentry (ESTATE) in England (E-) and Ireland (-STATE) (ESTATE),
21 Mistakes (ERRORS) engineering (E-) on Rolls Royce (-RR-) is the ‘gold (gold colour = -OR-) standard’ initially (‘standard’ initially = -S) (ERRORS),
23 Rows (OARS) with co-authors losing touch (‘co-authors’ losing ‘touch’ = aors = OARS),
24 Gas fitter drops rates (‘gas fitter’ drops ‘rates’ = gfit = GIFT) for the present (GIFT).