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
8 A caring aunt, mostly works from somewhere in Central America (10) NICARAGUAN {A+CARING+AUNt}*
9 Men in uniform, mostly are mighty heartless (4) ARMY {ARe}{Mi..tY}
10 Gathered publicity tool used by The Carpenters (4) ADZE (~ads)
11 Boring place that lulls devil's flares (10) DULLSVILLE*
18 Lacking originality and slightest of tenacity, author is without work (5) TRITE {Te...y}{wRITE}
21 Quarrel little about securing the one who feeds us all (6) TILLER [T<=]
23 Regularly carry small sort of latest radio receiver (7,3) CRYSTAL SET {CaRrY}{S}{LATEST*}
25 Married old boy with second family (4) MOBS {M}{OB}{S}
26 Almost like holding piece of cheap fleece (4) SCAM {S{Ch..p}AMe}
27 One by one captured leaders of the Indian right, running in excited manner (10) STIRRINGLY {S{The}{In...n}{Ri..t}{Ru...g}INGLY}
DOWN
1 Women in popular party, work for opening (6) WINDOW {W}{IN}{DO}{W}
2 Heal perhaps to become healthy! (4) HALE*
3 Cart overturned by skilled railway supervisor (10) YARDMASTER {DRAY<=}{MASTER}
4 I chip in with zest, excited after boy returned holding universal kind of nationality (4,11) DUAL CITIZENSHIP {I+CHIP+IN+ZEST}*<=>{LA{U}D}<=
5 Bishop avoided extra responsibility (4) ONUS bONUS
6 Where kids play with a clamour, good sort of polo (6,4) WADING POOL {W}{A}{DIN}{G}{POLO*}
7 Use filmy conditions like 'mix oil and water' (8) EMULSIFY*
13 Cold, soil coloured and little unwieldy (10) CUMBERSOME {C}{UMBER}{SOME}
15 Time, little time, small time or minutes for online controversy (10) TWEETSTORM {T}{WEE}{T}{S}{T}{OR}{M}
17 England charging in correct direction with single idea (3-5) O?E-?R?C? (Addendum - ONE-TRACK {ON{E}TRACK} - See comments)
22 Preserve body with half of egg and bare palms (6) EMBALM {EMBryo}{pALMs}
24 Naked mistakes on part of church (4) APSE lAPSEs
25 Workers Union Card (4) MENU {MEN}{U}
Reference List
King = K, With = W, Popular = IN, John = LOO, Work = W, Small = S, Married = M, Old Boy = OB, Second = S, Women = W, Popular = IN, Party = DO, Universal = U, Bishop = B, Good = G, Cold = C, Time = T, Minutes = M, English = E, Union = U