Across:
8 Has done more than most to change what’s on television (REMOTE) in the sticks (REMOTE),
9 Pain in the neck perhaps (HEADACHE) on top of everything else (HEAD-), as it’s initially awkward (initially “awkward” = -A-) and revolutionary (-CHE) (HEADACHE),
10 Hates leaving sunbather (‘hates’ leaving ‘sunbather’ = unbr = BURN) to soak up too much of the sun (BURN),
11 The boarding house, in a Joycean sense (The Boarding House is a SHORT STORY in James Joyce’s Dubliners), opens in 7 down (opens in ‘short-run’ = SHORT) with school (S-) that’s conservative (-TORY) (SHORT STORY),
12 Scott leaves combat boots (‘Scott’ leaves ‘combat boots’ = mbaboo = BAMBOO) in grass (BAMBOO),
14 It’s required by anyone looking to get out of prison, for instance (PASS-), for part of the sentence (-WORD) (PASSWORD) – would that be the key? (PASSWORD),
15 Places where the people can make their mark (POLLING STATIONS) or for those who want to make alterations in the house perhaps (POLLING STATIONS),
18 One member of overseas Special Forces (SEAL) nearly (l) (‘seal’ without ‘l’ = SEA-) gets drunk at The Tap (WATER) (SEAWATER) – it holds the ship up! (SEAWATER),
20 Set free (RESCUE) or twist (= anagram indicator) secure (secure = RESCUE),
22 Awful outcry (BLUE MURDER) sounds like it could be to do with regicide, in a bloody colourful way? (regicide = killing of a king/blue blood = BLUE MURDER),
24 Bengals drop ban (‘Bengals’ drop ‘ban’ = egls = LEGS) in stages (LEGS),
25 Father won’t hear of it from childish type (BACKCHAT) offering support (BACK-) for Switzerland (-CH-) removing top (v) tax (‘vat’ without ‘v’ = -AT) (BACKCHAT),
26 Parking (P-) on lane (“lane” = “lain” = -LAIN-) sounds like (= homophone indicator) it’s close to school (-S) (PLAINS) in flatland (PLAINS).
Down:
1 Amused (amused = MEDUSA) criminal (= anagram indicator) from Greece with snaky dreadlocks (MEDUSA),
2 Cash advance (LOAN) for removing mice from coal mine (removing ‘mice’ from ‘ coal mine’ = oaln = LOAN),
3 Opens to a (opens to a = TEASPOON) knock (= anagram indicator) from one of those capable of causing quite a stir (TEASPOON),
4 Get lost (SHOO) in short (t) film (‘shoot’ without ‘t’ = SHOO),
5 Prickly sort (CACTUS) of college (C-) plays a part (acts = -ACT-S) covering start of the uncertainty (start of the ‘uncertainty’ = -U-) (CACTUS),
6 Makes everyone toe the line in the house (PARTY WHIPS in The House) band (PARTY) to do the mix with Cream (WHIPS cream) (PARTY WHIPS),
7 Manage (-RUN) to get behind (= positional indicator) type of film (SHORT-) (SHORT-RUN) for brief period (SHORT-RUN),
13 Where you’d expect to find underground boss (expect to find the devil = BELOW) – in the hands of the dealers (DECKS) (BELOW DECKS) downstairs in The Yacht (BELOW DECKS),
14 Show off (POSER) enigmatic (= anagram indicator) prose (prose = POSER),
16 Resistance (r) replaces American leader (‘America’ leader = -A-) for June 6th landing (June 6th Normandy landing / “Overlord”) (‘overlord’ to replace ‘r’ with ‘a’ = OVERLOAD) in swamp (to swamp it = to OVERLOAD it),
17 Broadcast (AIR -) on small amounts (-DROPS) (AIR-DROPS) of supplies given to the troops (AIR-DROPS),
19 What’s the point (point in fencing = TOUCHE) in saying you got me there clever clogs! (acknowledge a valid point / clever remark ‘touché’ = TOUCHE),
21 Old city (UR-) fellow (-GENT) (URGENT) demands immediate action (URGENT),
23 Cameron isn’t part of documentary (‘Cameron’ isn’t part of ‘documentary’ = duty = DUTY) out of loyalty (DUTY),
24 The first to go (LEAD) out of shot in the war sense (LEAD bullet).