Across:
1 Starter of 11 down (starter of 'fruit picking = FRUIT-) with endless (end 'lesS' = -S) (FRUITS) bananas (FRUITS),
4 Monitor (OBSERVE-) resistance (-R) (OBSERVER) to witness (OBSERVER),
9 University (U-) in Tonga (Tonga) designed (= anagram indicator) (Tonga = NO-GAT) (NOUGAT) by nutty, sweet type (NOUGAT),
10 Putting away (STASHING) one of those in the forest (-ASH-) caught in police operation (sting = ST-ING) (STASHING),
12 The first in a manner of speaking (INAUGURAL) that’s popular (= IN-) late summer (August = AUG-) on Russian River (-URAL) (INAUGURAL),
13 Refuse to accept (reject) starting off (r) (‘reject’ without ‘r’ = EJECT) in exile (EJECT),
14 Issues raised by new Union (STEPCHILDREN) relates to more than one of those in 18 across (more than one ‘stepdaughter’ = STEPCHILDREN),
18 The second mate’s kid (STEPDAUGHTER) held up (= reverse indicator) cats and dogs (pets = STEP-) for mother’s close relative (DAUGHTER) (STEPDAUGHTER),
21 Cast (TRAWL) from Dragnet? (drag net = TRAWL),
22 Announce (= homophone indicator) Czech (‘Czech’ = ‘CHECK-’) composer (Franz Liszt) on the radio (= homophone indicator) (‘Liszt’ = ‘-LIST’) (CHECKLIST) with reminder of records (CHECKLIST),
24 The Jewel in The Crown (PICK) is not the first (‘Not’ the first letter = ‘N’) to combine (MIX) (PICK ‘N’ MIX) an assortment of sweets (PICK ‘N’ MIX),
25 One given a job solely for The Gathering (PICKER) at the start of 24 across (at the start of ‘pick ‘n’ mix’ = PICK-) in the middle of term (middle of ‘tERm’ = -ER) (PICKER),
26 You could say, Barney (EXCHANGE) produced One Direction (East = E-), Kiss (-X-) and Cash, loosely speaking (-CHANGE) (EXCHANGE),
27 No late (no late) shift (= anagram indicator) (no late = LEAN-TO) in temporary shelter (LEAN-TO).
Down:
1 A French ('a' French = -UN-) and a German ('a' German = ein) reflection (= reverse indicator) (ein = -NIE-) by Old Bob ('old bob' = shilling = -S-) in the paper (Financial Times = F-T) (FUNNIEST) is most amusing (FUNNIEST),
2 Loudly laments (ULULATES) university (UL) repeats (UL+UL = ULUL-) – a (-A-) set (set = -TES) back (= reverse indicator) (ULULATES),
3 Sounds like the plucky type (TWANG sounds like a musical instrument) from Dynasty (Tang dynasty = T-ANG) found around women (-W-) (TWANG),
5 What you might order in a bar – a bubbly beverage perhaps (sparkling water = BOTTLED WATER) – is put in a glass (BOTTLED) to drink (WATER) (BOTTLED WATER),
6 Seasonal gift (EASTER EGG) for awkward (= anagram indicator) eaters (eaters = EASTER), for example (e.g. = -EG-), close to starving (close to ‘starvinG’ = -G) (EASTER EGG),
7 Loses drive without Ross (‘loses drive’ without ‘Ross’ = ledive = VEILED) hidden from view (VEILED),
8 Works for newspaper (writes) reporting (= homophone indicator) (‘writes’ = ‘RIGHTS’) to some who are civil? (Civil RIGHTS).
11 Presumably, capturing Olive and Cherry (FRUIT PICKING) robbing an orchard perhaps? (FRUIT PICKING),
15 Persian (Persian CAT-) briefly (e) without help (‘alone’ without ‘e’ = -ALON-) introduces Iranian Ambassador (introduces ‘Iranian Ambassador’ = -IA) (CATALONIA) to a part of Spain (CATALONIA),
16 Showing great distress (STRICKEN) moving (= anagram indicator) nest (nest = ST-EN) with stack of straw (-RICK-) inside (STRICKEN),
17 Nothing (O-) to do with rising (= reversal indicator) pitch (tar = -RAT-) from old (-O-) group of musicians (trio) starting to go off (t) (‘trio’ without ‘t’ = -RIO) (ORATORIO) Handel’s Messiah, for example (Handel’s Messiah, for example = ORATORIO),
19 Part of dance (STEP-) exercise (-PE) (STEPPE) in large flat space (STEPPE grasslands),
20 Describes limestone (CALCIC) in California (CA-) and summits of larger chains in Colorado (summits of ‘Larger Chains In Colorado’ = -LCIC) (CALCIC),
23 Cocktail (‘cocK’ tail = K-) is fine (fine) – possibly (= anagram indicator) (fine = -NIFE) (KNIFE) it will take the edge off (KNIFE).