Solution to 28A has been deliberately left unsolved and is to be answered 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 answer, if not solved by 1 PM.
FIVE FIRSTS
ACROSS
1 I.A.S.-mess-rejected paneer is cooked for groom (5) PREEN {PaNEER+is}*
4 Think, essentially during rehabilitating, dad's peer lost hope (9) DESPAIRED {thInk}* in {DADS+PEER}*
11 "Am like this" statement of kinky person's sex life (4-10) SELF-EXPRESSION {PERSONS+SEX+LIFE}* {PERSONS+SEX+LIFE}*
12 Has secretly grown stronger (4) OWNS [T]
13 Internal communication terminals? Never send shocking letters (5,4) NERVE ENDS*
17 Brought balance to English squad? Lie, unfortunately (9) EQUALISED {E}{SQUAD+LIE}*
19 So savage, revolting! (4) ERGO<=
22 Typical daily routine, retired father's habit (14) CHARACTERISTIC {CHAR}{ACT}{SIRE<=}{TIC}
25 Muslim League Dr. regularly rejected separation theory? (7) DUALISM {MuSlIm+LeAgUe+Dr}<=
26 Call mum, son's misbehaving (7) SUMMONS*
27 Thought Tendulkar initially did umpiring all around (9) MEDITATED {MEDI{Te...r}ATED}
28 Jam? Badgers not sure (5) P?E?S ()
DOWN
1 Whisper: "Is cop ethically carrying navy instrument?" (9) PERISCOPE [T]
2 Greek character cycled solo, drinking sip after exercising (7) EPSILON {(+e)ELON(-e)} over {SIP}*
5 Film mount (5) SCALE [DD]
6 Cadet, set target somewhat westward; confirmed? (8) ATTESTED [T<=]
7 Nocturnal creature gallivanting on a croc (7) RACCOON*
14 Put right colour on unfinished sweet after flipping (9) REDRESSED {RED}{DESSERt<=}
15 Arrays of small pipes constraining toilet area (9) SHOWCASES {S}{HO{WC}{A}SES}
16 Philanthrope, gangster, one inspired by faith (8) ALTRUIST {AL}{TRU{1}ST}
18 Never listened to you (reportedly) and her frolicking (7) UNHEARD {(~you)U)(AND+HER}*
20 Fury wife unleashed on staff, blowing top for dirty room (7) RATHOLE {wRATH}{pOLE}
21 Stabilise tree stump, cutting 40% off (4,2) FIRM UP {FIR}{stUMP}*
23 Around peak of Olympus, encountered heavenly sight (5) COMET {C}{Ol...s}{MET}
Reference List
Time = T, English = E, Minute = M, Tenor = T, Small = S, Toilet = WC, Area = A, Gangster = AL(Capone), Wife = W, Around = C, Depth = D, Tense = T