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 answer, if not solved by 1 PM.
ACROSS
1 Reviewed excellent book in outstanding discussion (8) DIALOGUE {D{A1<=}{LOG}UE}
10 Rocky after end of round, knocked out (7) DRUGGED {RUGGED}<=>{r..nD}
11 Implants hip with small incision, revolutionary (7) INSTILS {IN}{S}{SLIT<=}
12 Tongue in meal at inn (5) LATIN [T]
13 Turning surgical beam around, pick up drill (9) REHEARSAL {RE{HEAR}SAL<=}
14 Remarkably on a roll, fine girl is uncompromising (3-2-7) ALL-OR-NOTHING {ON+A+ROLL}*{THIN}{G}
18 & 23 Where surfer might be enjoying a run of success (2,3,5,2,1,4) ON THE CREST OF A WAVE [DD}
21 Displays a rampant, abnormal growth of cells (9) DYSPLASIA*
23 See 18
24 Unruly imp about to devour English dish (4,3) MEAT PIE {M{EAT}PI*}{E}
26 New drug smuggled by reckless drug pusher (6) NUDGER {N}{UDG{E}R*}
27 Old film about time travel at inauguration is theatrical (8) OPERATIC {O}{P{ERA}{Tr...l}IC}
DOWN
1 Led astray after drinking rum in picnic (6) DODDLE {D{ODD}LE*}
2 Sharpness of unionist in American town (6) ACUITY {A}{C{U}ITY}
3 Egg allergen affected specialised part of cell (9) ORGANELLE {O}{ALLERGEN*}
4 Sick, surrounded in wraps - man's emaciated (14) UNDERNOURISHED {SURROUNDED+IN}* over {HE}
7 Error to capture pawn after time trouble in state of panic (8) TAILSPIN {S{P}IN}<=>{T}{AIL}
9 Perky comedian perfects voice-over without distress (4,4,4,2) WITH ONES TAIL UP {WIT}{HONES}{T{AIL}UP<=}
15 Favoured fork to eat salad (4,5) TOOK AFTER*
16 Hunters pursue small opossum finally into lair (8) WOODSMEN {WOO}{D{S}{o...uM}EN}
17 Reportedly international model turned despondent, tackling bulimia essentially (2,2,4) ?T ?S ?A?D (Addendum IT IS SAID {I}{SIT<=}{SA{bulImia}D} - See comments)
19 Importance of pain in both sides of chest (6) CACHET {Che{ACHE}sT}
20 Feverish man with cold and spasm (6) HECTIC {HE}{C}{TIC}
22 Slip in base after drinks (5) LAPSE {E}<=>{LAPS}
Reference List
Husband = H, Women = W, Hip = IN, Small = S, Girl = G, English = E, Model = T, New = N, Drug = E, Old = O, Unionist = U, American = A, Son = S, Pawn = P, Time = T, Institute = I, International = I, Cold = C, Base = E