Across:
8 Pilots not part of relationship (‘pilots’ not part of ‘relationship’ = reainh = HERNIA) – on a human level, it’s a sign of rupture (HERNIA),
9 It’s not right (IMPROPER) or wrong? (IMPROPER),
10 Permits (permits/allows = LETS) for opening 25 across (opening ‘lets down’ = LETS),
11 Put off (DISCOURAGE) by gracious (gracious = -ISCOURAG-) model (= anagram indicator) in Germany (Germany domain = .de = D-E) (DISCOURAGE),
12 Leggy type (TENDON) upsets (= reversal indicator) Bob (nod = -DON) Hook? (hook/net = TEN-) (TENDON),
14 A way (away = OUT-) for opening (-DOOR-) beers at the foundation (‘beerS’ at the foundation = -S) (OUTDOORS) exposed to the elements (OUTDOORS),
15 Is this the advice Rapunzel got from Prince (LET ONE’S HAIR DOWN) to unwind? (LET ONE’S HAIR DOWN),
18 Ms Monroe (Ms Monroe) dancing (= anagram indicator) (Ms Monroe = MEN’S ROOM) with the gents (MEN’S ROOM),
20 Trespassers drop pears (‘trespassers’ drop ‘pears’ = trssse = STRESS) with anxiety (STRESS),
22 Yank (TOW-) noticed start of (‘Noticed’ start of = -N) recent (recent) trouble (= anagram indicator) (recent = CENTRE) (TOWN CENTRE) in urban shopping area (TOWN CENTRE),
24 A leak that has to be fixed (DRIP) on both sides of dry cargo ship (on both sides of ‘DRy cargo shIP = DRIP),
25 Old newts (old newts) all over the place (= anagram indicator) (old newts = LETS DOWN) in deserts? (LETS DOWN),
26 Lowest (lowest) collection (= anagram indicator) (lowest = TOWELS) in the linen press (TOWELS).
Down:
1 Cut out (DELETE) flower (Flower /River Dee = DE-E) found around accommodation (accommodation / let = -LET-) (DELETE),
2 Individuals (ONES) happy to leave pay-phones (‘happy’ to leave ‘pay-phones’ = ones = ONES),
3 Major steps taken (WAR DANCE) by one of those prior to the Battle of Charleston presumably (WAR DANCE before or after a battle + Charleston dance),
4 Feel nostalgic for (MISS) what borders on midsummer madness (what borders on ‘MIdsummer madneSS’ = MISS),
5 Relative (Pop) loses the head (p) (‘pop’ without ‘p’ = OP-) with local informer? (tout = -T OUT) (OPT OUT) Don’t get involved! (OPT OUT),
6 Presumably, when Old King Cole called for his pipe and called for his bowl? (COURT ORDER) I heard that one in a room full of barmen! (COURT ORDER),
7 Security (HEDGE-) racket (racket/fight = -ROW) (HEDGEROW) relates to Protection all along The Border (HEDGEROW),
13 Presumably, you’ll be going out at night in that state (DROWSINESS) – and that’s supposed to eventually put your mind at rest? (DROWSINESS),
14 Old characters synonymous with The Script (ancient Irish + British alphabet = OGHAM) made a lasting impression on The Stones (OGHAM alphabet often inscribed on stone),
16 Study (EYE-) problems for the ramblers (-SORES) (EYESORES) in areas with too many ugly weeds (EYESORES),
17 Local gives someone a going over (local ‘gives someone a going over’ = INSPECTS) in vets? (vets/examines = INSPECTS),
19 State (OREGON) of REM leaving green room (‘REM’ leaving ‘green room’ = grenoo = OREGON),
21 Occupy one’s time (-KILL- time) in ship (SS = S-S) (SKILLS) with one’s gifts (SKILLS),
23 Statesman missing a Mass (‘statesman’ missing ‘a mass’ = tten = TENT) in temporary accommodation (TENT),
24 Finishes 25 across (finishes ‘lets down’ = DOWN) in the north of Ireland (DOWN).