Solution to 28A 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 answer, if not solved by 1 PM.
ACROSS
10 For the most part, Tata Ace transports vitamin and salt (7) ACETATE {TATa+ACE}*{E}
11 Famous specialist follows eastern time (7) EMINENT {ENT}<=>{E}{MIN}
12 Copper nabs snitch with soldier's attendant (7) CURATOR {CU}{RAT}{OR}
15 Drive to Marrakesh over partly (5) SHOVE [T]
16 Special wine (cold) altered muscle tone (7) SPASTIC {SP}{ASTI}{C}
19 By deceit, cash given to sister's used to frame (7) CHASSIS {CASH*}{SIS}
20 Gain a male animal (5) AMASS {A}{M}{ASS}
26 At the start, sudden noise baffled son entering a meeting (7) SESSION {Su...n}with {NOISE}*over {S}
28 Nurse corresponding with leading endocrinologist to join (7) E?T?I?E (Addendum - ENTWINE {EN}{TWIN}{En...t} - See comments)
29 Son's team centre joins another team at beach (7) SEASIDE {S}{tEAm}{SIDE}
DOWN
1 Touch actress badly to lose front tooth (6) CARESS ACtRESS*
2 Goods arriving without name (6) LADING LAnDING
3 Limits excess centrally from rodents (4) MICE {liMIts}{exCEss}
4 Spy's article creates rage (6) SEETHE {SEE}{THE}
5 Unruly trio can, at the border, clandestinely get controlled substance (8) NARCOTIC {TRIO+CAN}*{Cl...y}
6 Downer from French media worker (10) DEPRESSANT {DE}{PRESS}{ANT}
7 Careful about one in car, say at America (8) CAUTIOUS {C}{AUT{1}O}{US}
8 Its unique; spy replaces man with lady in difficulty (8) PEERLESS {PEER}{(-m+l)LESS}
18 Client of Atticus, Tom, Eric protected (8) CUSTOMER [T]
22 Leading an animal to the front provides benefit (6) ASSIST {1ST}<=>{ASS}
24 Say, diva spotted in a bus in Germany (6) SINGER [T]
27 Collect sample of son and wife to get blood group (4) SWAB {S}{W}{AB}
Reference List
Vitamin = E, Specialist = ENT, Eastern = E, Snitch = RAT, Soldier = OR, Special =SP, Cold = C, Male = M, Son = S, Nurse = EN(Enrolled Nurse), Name = N, From in French = DE, About = C, Man = M, Lady = L, South = S, Wife = W, Blood Group = AB