This week's puzzle is another which Gregson suspects will sharply divide opinion among solvers, between those who spotted the solution almost immediately and those who spent hours fruitlessly chasing red herrings round the grid. Gregson's own particular red herring was the sardine waiting to be eaten in the bottom of the grid!
The first letters of the extra words in clues spell out SECOND AND TENTH LETTERS OF CLUES EYE FACE HAND NECK. The second letters of clues spell out SCAN ALL DIAGONALS CENTRE OF GRID AND KNIGHTS MOVES. The tenth letters of clues spell out BLOATER KIPPER ROLLMOP FIVE BY FOUR SUPERIOR MODEL.
Eye, face, hand and neck can all be red and bloater, kipper and rollmop are all herrings so these are all to be ignored. The diagonals and knight's moves are also, less obviously, to be ignored as red herrings. This leaves the five by four centre of the grid where EDHE[SO][UA] can be found inside TINTINNABULATE. Replacing the clashing letters by RR leaves something to be interpreted as EDHERR inside RING, or REDHERRING.
The extra words in clues are shown highlighted in bold.
ACROSS
1 Oscar stumbled after parking and perished holding broken bottle shaped
like a cone (12)
POTTLE-BODIED (P (parking) + O (Oscar) + DIED (perished) round anag of
bottle))
9 Echinops flower in Sussex displays a redness from behind (4)
ADUR (A + RUD (redness) rev)
11 Candlenut oil is a fermented drink (5)
SAVIN (S (is) + A + VIN (fermented drink))
13 Unsavoury alcoholic drinks half turn stomachs over (7)
ROTGUTS (half of ROTATE (turn) + GUTS (stomachs))
14 Racket nettles reprobate when final pawn is taken (4)
SCAM (SCAMP (reprobate) minus P (pawn))
15 Blood vessels' fragility protected by this titanium deflector in flow
(5)
RUTIN (RUN (flow) round TI (titanium))
16 Alpine entrance is a glory neither soft nor hard (6)
ATRIUM (A + TRIUMPH (glory) minus P (soft) and H (hard))
17 Adjust broken rein to nag (6)
ORIENT (anag of REIN TO)
18 Dick's barking mad - take away liquid container! (6)
INK-BAG (anag of BARKING minus R (take))
19 Tailors, oppressed by the truck system, kicked around man-machine interface
(7)
TOMMIED (TOED (kicked) round MMI (man-machine interface))
22 Egotists approach initially, then turn back (3)
AGO (A (first letter of approach) + GO (turn))
23 Cowardly dean hit niece after straying (12)
FAINT-HEARTED (anag of DEAN HIT AFTER)
26 Ancient form of tendon and muscle disease (3)
ALS (double def)
28 Hang-gliders are situated immediately below the terminal after advance
(7)
SUBTEND (SUB (advance) + T (the) + END (terminal))
30 All follow offspring in Lowry's composition (6)
SONATA (SON (offspring) + AT (in) + A (all))
31 Essentially a period of five years distinction (6)
LUSTRE (double def)
34 Eccentric lads ran without hint of tired legs for stop (6)
NASARD (anag of LADS RAN minus L (first letter of legs))
36 Technical minds are admitted by Civil Service (5)
CARES (CS (Civil Service) round ARE)
37 Engaging doctrines are singularly empty misconceptions (4)
ISMS (IS (are singularly) + MS (first and last letters of
misconceptions))
38 "It was the epoch of belief", written by him - the Russian devil!
(7)
DICKENS (ref to quotation from The Tale of Two Cities)
39 Trounced after loss of bishop upset strategy (5)
EATEN (BEATEN (trounced) minus B (bishop))
40 Perhaps a wigeon is almost overly tame (4)
SMEE (S (is) + MEEK (tame) minus last letter)
41 Does war favourite scorn exceptionally negative results? (12, two
words)
NO-SCORE DRAWS (anag of DOES WAR SCORN)
DOWN
1 A fan chanted "poor shirt" rudely and repetitively (13)
PARROT-FASHION (anag of A FAN POOR SHIRT)
2 Again, ladybirds taken in by our scent (5)
ODOUR (OUR round DO (again))
3 Dry in honey guide's underground passage where everybody's singing
(5)
TUTTI (TUI (honey guide) round TT (dry))
4 Piece of enforested land in Paris is destroyed (6)
ESTATE (EST (is in French) + ATE (destroyed))
5 A debt is sportingly settled for a house in the country (7)
BASTIDE (anag of A DEBT IS)
6 Eater in study of excess (4)
OVER (double def)
7 In young Caribbean country the heartless brood (8)
INCUBATE ( IN + CUBA + THE minus middle letter)
8 Edwardians' failures include improper dodges for heroines
(13)
DEMIGODDESSES (DEMISES (failures) round anag of DODGES)
10 Skewed end unit frames explosive (7)
DUNNITE (anag of END UNIT)
12 Anchors in Perth millstream alongside yellow wreck (6)
DAMAGE (DAM (Scottish millstream) + AGE (yellow))
14 Circling deer hard for a religious adherent (4)
SIKH (SIKA (deer) with H (hard) replacing A)
20 Egyptian wrongly identifies young girl embracing celebrity (8)
MISNAMES (MISS (young girl) round NAME (celebrity))
21 Character in opera company hopelessly pursues withdrawn islander
(7)
NABUCCO (CUBAN (islander) rev + CO (company))
24 Atypical poet from Spain unequivocal on sonnet's passage (6)
ALONSO (hidden)
25 Ashen-grey revolutionary upset near squirrel (7)
HOARDER (HOAR (ashen-grey) + RED (revolutionary) rev)
27 Omit diplomatic move over critical position (4)
PASS (triple def)
29 Composition of lead in Naples named in honour of Venetian (6)
ALDINE (anag of LEAD IN)
32 Evil-minded master pursues Tech's head concerning opening (5)
TREMA (T (first letter of Tech) + RE (concerning) + MA (master))
33 Begin career again joining Frenchman and wife (5)
RENEW (RENE (Frenchman) + W (wife))
35 A singer killed (4)
ALTO (A is abbreviation for alto)