Across:
8 Mother (-MA-) taken in by visitor to Oz (Toto = TO-TO) (TOMATO) offering fruit (TOMATO),
9 Croaky (hoarse) on the radio (= homophone indicator) (‘hoarse’ = ‘horse’ = HORSE-) and on local television (-BOX) (HORSEBOX) in the trailer for Black Beauty (HORSEBOX),
10 Stay away from play list (‘stay’ away from ‘play list’ = plli = PILL) from Tablet (tablet/pill = PILL),
11 Potentially serious challengers (CONTENDERS) from movement (= anagram indicator) censored (censored = CO-ENDERS) over good books (New Testament = -NT-) (CONTENDERS),
12 Assistance sought (HELP-) in hospital (-ER) (HELPER) for right-hand man (HELPER),
14 Keep under control (RESTRAIN) with Cross (= anagram indicator) Trainers (trainers = RESTRAIN),
15 Making something clear (TRAINING) to potential bachelors (COLLEGE) (TRAINING COLLEGE) from educational institute (TRAINING COLLEGE),
18 Victor (-V-) or (-OR-) Charlie (-C-) lost power in the car (DI-ED) outside (DIVORCED) of Split (split = DIVORCED),
20 Agreed to be taken out of ringside seat? (‘agreed’ to be taken out of ‘ringside seat ‘ = insist = INSIST) That’s it – I kid you not! (INSIST),
22 Underground figure (Greek god of the underworld = Hades or = PLUTO-) caught (-C-) with informers (-RATS) (PLUTOCRATS) by rich people (PLUTOCRATS),
24 Well, it’s not (SICK) the case that you need 10 across? (SICK need ‘pill’),
25 A sincere (a sincere) adaptation (= anagram indicator) (a sincere = INCREASE) of Spiral (Spiral = INCREASE),
26 Comic (jocular) loses the head (j) (‘jocular’ without ‘j’ = OCULAR) – it’s to do with the viewers? (OCULAR).
Down:
1 Cultured (POLITE) European (POL-E) possesses it (-IT-) (POLITE),
2 The Post (the post = MAIL) produced up (= reverse indicator) in Williamsburg (in ‘wilLIAMsburg’ = liam = MAIL),
3 Compositions (CONCERTI) of cycle (C-) clubs (-C-) in Orient (Orient) all over the place (= anagram indicator) (Orient = -ON-ERTI) (CONCERTI),
4 Give a wide berth to (SHUN) hothead (‘Hot’ head = -H-) in paper (Sun = S-UN) (SHUN),
5 Politicians (GREENS) – presumably, they started off in 6 down? (GREENS presumably, they started off in ‘seed drills’),
6 Genesis (SEED) drummer, lead (‘Drummer’ lead = D-) guitar, ultimately (‘guitaR’ ultimately = -R-) having problems (ills = -ILLS) (SEED DRILLS) with Farm Aid’s distributing down the line (farm aids distributing down the line = SEED DRILLS),
7 It’s not easy (it’s hard = H-ARD-) welcoming order (-O-) in (-IN-) Government (-G) (HOARDING) that amounts to regular savings (HOARDING),
13 Life (life = PRISON TERM) sentence? (sentence = PRISON TERM),
14 Firm (RIGID) in Arctic (frigid) needs no introduction (f) (‘frigid’ without ‘f’ = RIGID),
16 It’s about (RE = R- -E) including a (-A-) week (week) speaking (= homophone indicator) (‘week’ = ‘weak’ = ill = -IL L-) on popular (-IN-) (RAIL LINE) transportation system going from station to station (RAIL LINE),
17 Leaving out (OMISSION) nothing to do (O-) with life’s work perhaps (-MISSION) (OMISSION),
19 Hot drinks (COCOAS) with two officers (Commissioning Officer x 2 = CO+CO = COCO-) from American (-A-) base on Bahamas (base on ‘bahamaS’ = -S) (COCOAS),
21 Fled from coalfields (‘fled’ from ‘coalfields’ = coails = SOCIAL) for The Gathering (SOCIAL),
23 Takes a very long time (AGES) for the Wise Guys (sages) to head off (s) (‘sages’ without ‘s’ = AGES),
24 Take no notice of (SNUB) upside-down (= reverse indicator) cakes from the bakery (buns = SNUB).