Across:
8 Parents (Da + Ma = DAMA-), for example (e.g.), upset (= reversal indicator) (eg = -GE) (DAMAGE) by vandalism (DAMAGE),
9 Legend (‘leG’ end = G-) gets nothing from tennis (-LOVE- score), from fight in the ring (-BOX in the boxing ring) (GLOVEBOX) or from one of the handy types in golf? (handy type in VW Golf car = GLOVEBOX),
10 Quick trip (SPIN) around Spanish Main (around ‘SPanish maIN’ = SPIN),
11 14 across (‘electric’ = ELECTRIC-) is a (-A-) student (learner = -L) (ELECTRICAL) potentially with a bit of spark (ELECTRICAL),
12 Peter’s (peters) treatment (= anagram indicator) (peters = PRESET) is arranged in advance (PRESET),
14 The lead in 15 across (lead in ‘electric blanket’ = ELECTRIC) – the one lighting up The Wire (ELECTRIC),
15 Exciting (ELECTRIC) Kent Lab (Kent Lab) cooking (= anagram indicator) (Kent Lab = BLANKET) (ELECTRIC BLANKET) something that gradually heats up and is put over a single? (ELECTRIC BLANKET),
18 Pet deals (pet deals) arranged (= anagram indicator) (pet deals = PEDESTAL) by Foundation (foundation/base = PEDESTAL),
20 Turns up (= reverse indicator), for example (e.g. = -GE), to study (den = -N ED-) at Oxford (O-) (ON EDGE), a bundle of nerves (ON EDGE),
22 What to do if you want to know how to blow your own trumpet (STUDY MUSIC)? Master how one recognises staff synonymous with bars! (master musical staff synonymous with musical bars / STUDY MUSIC),
24 Roll (REEL) with innards of perch (innards of/middle letter of ‘peRch’ = R-) – a long, snaky fish? (-EEL) (REEL),
25 Covers (BLANKETS) for those characters at the end of 15 across (end of ‘electric blanket’ = BLANKET-) at school (-S) (BLANKETS),
26 With these types of vacancies to fill (BLANKS), firing them will achieve nothing (firing BLANKS).
Down:
1 Nero's not included in proper names ('Neros' not included in 'proper names' = prpeam = PAMPER) for baby? (baby/spoil = PAMPER)
2 Uplifting (= reversal indicator) characters from Unforgiven, Rawhide (characters from ‘unforgiveN RAWhide’ = nraw = WARN) and Sound the Alarm (WARN),
3 See red (see red) mysteriously (= anagram indicator) (see red = DESE-ER) over retweet (-RT-) (DESERTER) from one on the run from The Troubles (DESERTER),
4 Stuffed into leather goods (stuffed into ‘leathER GOods’ = ergo) switched (= reverse indicator) (ergo = OGRE) by pantomime villain (OGRE),
5 Gang of eight leaders (‘Gang Of Eight’ leaders = GOE-) – most (m) of them (them) (‘them’ without ‘m’ = -THE) (GOETHE) responsible for the sorrows of young Werther? (Johann Wolfgang von GOETHE responsible for/wrote “The Sorrows of Young Werther”),
6 Lack of enthusiasm (RESISTANCE) for The Underground perhaps (RESISTANCE),
7 Divide people (POLARISE) by broadcasting (= anagram indicator) a spoiler (a spoiler = POLARISE),
13 Following (SUCCEEDING) school (S-), go to university (University College Cork = -UCC-), paying attention (heeding) starting off (h) (‘heeding without ‘h’ = -EEDING) (SUCCEEDING),
14 Stand out (EXCEL) or up (= reverse indicator) river (River Lee = E-EL) guarding hundred (-C-) and ten (-X-) (EXCEL),
16 Don’t move (LIE STILL) as they may come in a pack (pack of lies = LIE S-) for the cash register (till = -TILL)? (LIE STILL),
17 Sounds like (= homophone indicator) family (‘line’ = ‘LION’) taking empty (r) parking places (curbs) (‘curbs’ without ‘r’ = CUBS) (LION CUBS) for those younger Pride members (LION CUBS),
19 It (it = TI-) upsets (= reversal indicator) English honour (-MBE-) by writing (from the 3Rs = -R) (TIMBER) to The Board (wood/board = TIMBER),
21 Leaves a bad smell in the air (-REEKS) after (= position indicator) first goal (first ‘Goal’ = G-) for (GREEKS) for Ajax and others (GREEKS),
23 Peels off shapeless (‘peels’ off ‘shapeless’ = shas = SASH) type of window (SASH window),
24 Nearly (y) raring to go (ready) (‘ready’ without ‘y’ = READ) in study (READ).