No 14389, Thursday 23 Jan 2025, Afterdark

Solution to 17D has been deliberately left unsolved and is to be answered only by a non-regular / novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance. 

Open for anyone to solve, if not solved by 1 PM.

ACROSS

1   Trainee at 1, working with a league that's global (13) INTERNATIONAL {INTERN}{AT}{1}{ON}{A}{L}

10 Trouble! Umbrage in HR for food (9) HAMBURGER {H{UMBRAGE*}R}

11 Fellow rides horse into vacant observatory, as it is cloudy (5) FOGGY {F}{Ob...{GG}...rY}

12 Message on medium that's spoken (5) MORAL {M}{ORAL}

13 Hector altering square shapes (9) TRIANGLES {ALTERING}*{S}

14 Sister-in-law cut deeply by a metal (6) SILVER {S-I-L}{VERy} 

16 Placed face on the other side (4) LAID<=

19 Satisfactory show (4) FAIR [DD]

20 Hold stranger in shower (6) RETAIN {R{ET}AIN}

25 Eva's talk about power was dry (9) EVAPORATE {EVA}{ORATE} over {P}

26 Joker working in train (5) WAGON {WAG}{ON}

27 Zepto trading bear and another animal (5) ZEBRA {Z}{BEAR*} Z/Zepto?

28 Explain 38% discount in interest given before time (9) INTERPRET {INTER}{PRE}{T} (38% = 1-5/8)

29 Somehow I termed people to have willpower (13) DETERMINATION {I+TERMED}*{NATION}

DOWN

2   To work on sum, learn numbers (8) NUMERALS*

3   If it is taken out tequila and distilled, it will be the same (5) EQUAL tEQUiLA*

4   Deny scandal at New England (6) NEGATE {GATE}<=>{NE}

5   Lit with beer and bit of rum, lousy, awful (8) TERRIBLE {LIT+BEER+Rum}*

6   Unpleasant attack (9) OFFENSIVE [DD]

7   Investors giving answer across backstage (6) ANGELS {AN{LEG<=}S}

8   Outside of CIT, chemistry is delivered as songs (6) RHYMES cHEMiStRY*

9   A nomad, fraud, heartless scally (5) GYPSY {GYP}{Sc..lY} 

15 Lifting beer, boater is forced to be careful (9) ELABORATE {ALE<=}{BOATER*}

17 Creature on paper is moving at the corner (8) ?R?A?I?M ()

18 Jumper is made by knitting angora in fine retreat (8) KANGAROO {ANGORA}* in {OK<=}

21 At this age, one is saturnine typically, reserved (6) NINETY [T]

22 Look, a zebra's head is inside, take it (5) SEIZE {SE{1}{Ze..a}E}

23 Rock children's game (6) MARBLE [DD] Marble is the toy and the game is Marbles

24 Lost to Dube at England, not entirely (6) BEATEN [T]

26 Fabric editor discarded was the most inferior (5) WORST WORSTed

Reference List

League = L, Fellow = F, Horse = GG, Medium = M, Square = S, Stranger = ET, Power = P, Time = T, New = N, England = E, Answer = ANS