Apologies for the very late blog. Thank you to Steerpike. Definitions are underlined in the clues.
Across
1. Claim form will get them an oddly aromatic drink (8,3)
CAMOMILE TEA : 1st, 3th, and subsequent letters in the odd (not even) positions of(… oddly) “Claim form will get them an”.
7/28. Limit restricting revolutionary soldier’s sleep (6)
CATNAP : CAP(a limit/an upper restriction) containing(restricting) reversal of(revolutionary) ANT(a social animal, one of whose castes is the worker).
9. Relating to a feature of Barcelona’s alleyways (5)
NASAL : Hidden in(of) “Barcelona’s alleyways”.
Defn: Relating to/about a facial feature, in this case the nose.
10. Anybody that initially was Hoover’s suspect holds key (9)
WHOSOEVER : 1st letter of(initially) “was” + anagram of(… suspect) HOOVER’S containing(holds) E(in music one of the keys/a group of notes forming the tone of a musical piece)
11. Writer from Australia backing the French on European measure (5,4)
EMILE ZOLA : [ Reversal of(… backing) OZ(informal term for Australia) + LA(French for the article “the”) ] placed after(on) [ E(abbrev. for “European”) + MILE(a unit measure of distance) ].
Answer: French writer.
12. Short poetry volume dismissed by critics, essentially (5)
TERSE : “verse”(a section of a poem/poetry) with “v”(abbrev. for “volume”) replaced by(dismissed by) middle letter of(…, essentially) “critics”.
13. Press caught on after second hint (7)
SOUPCON : [ OUP(abbrev. for the Oxford University Press) + C(abbrev. for “caught” in cricket scores) + ON ] placed after(after) S(abbrev. for “second” in time notation).
Defn: …/a trace of.
15. Hitch horse onto pole (4)
SNAG : NAG(an old or sick horse) placed after(onto) S(abbrev. for “South”, one of the geographic poles).
Defn: …/setback.
18. Stripped bones and wings of indigenous bird (4)
IBIS : “ribs”(bones in the chest) minus its 1st and last letters(Stripped …) plus(and) 1st and last letter of(wings of) “indigenous”.

20. Vague ending to story set upon small boat (7)
SKETCHY : Last letter of(ending to) “story” placed after(set upon) [ S(abbrev. for “small”) + KETCH(a two-masted sailing boat) ].
23. Scottish pretty heartlessly pursuing English in wood (5)
EBONY : “bonny”(Scottish for “pretty”/attractive) minus its middle letter(heartlessly) placed after(pursuing) E(abbrev. for “English”).

24. They’re left out of ordinary assignments (9)
OMISSIONS : O(abbrev. for “ordinary”) + MISSIONS(assignments/assigned tasks).
26. Fable about noble king making tough demand (4,5)
TALL ORDER : [ TALE(fable/story) containing(about) LORD(a high-ranking noble) ] + R(abbrev. for “Rex”, Latin for “king”).
27. Somewhat regret never overturning record (5)
ENTER : Hidden in(Somewhat) reversal of(… overturning) “regret never”.
Defn To ….
28. See 7 across
29. Odd PC turns out following electronic results (3,8)
END PRODUCTS : Anagram of(… out) ODD PC TURNS placed after(following) E-(prefix denoting things electronic, such as “email”).
Down
1. Summarise studies underpinnng Tory grandee’s conclusion (8)
CONDENSE : [ DENS(studies/rooms affording privacy and quiet) placed below(underpinnng, in a down clue) CON(abbrev. for a member of the Conservative Party/a Tory) ] + last letter of(…’s conclusion) “grandee”.
2. Setter’s desperate quest to encapsulate Italy’s powerful allure (8)
MYSTIQUE : MY(self-referential possessive pronoun for the writer, in this case, the setter) + anagram of(desperate) QUEST containing(to encapsulate) I(International Vehicle Registration code for Italy).
3. Scrap empty missile shelter (5)
MELEE : All inner letters deleted from(empty) “missile” + LEE(shelter against wind or weather provided by an object).
Defn: …/a brawl.
4. Clown dropping Charlie outside party with dope (7)
LOWDOWN : “Clown” minus(dropping) “C”(letter represented by “Charlie” in the phonetic alphabet) containing(outside) [ DO(a social function/party) + W(abbrev. for “with”) ].
Defn: …/the facts about a subject.
5. Type up entertaining article supporting justice for old people? (7)
TROJANS : Reversal of(… up, in a down clue) SORT(type/kind) containing(entertaining) [ AN(a grammatical article) placed below(supporting, in a down clue) J(abbrev. for “justice”) ].
Answer: People of ancient Troy.
6. A fight over fellow expert’s U-turn (5-4)
ABOUT-FACE : A + BOUT(a boxing or wrestling match/a fight) placed above(over, in a down clue) F(abbrev. for “fellow”) + ACE(an expert/one who excels, in a particular activity).
7. Caper movie’s central part accepted by struggling actor (6)
CAVORT : Middle letter of(…’s central part) “movie” contained in(accepted by) anagram of(struggling) ACTOR.
8. State prison guard historically releases knight (6)
TURKEY : “turnkey”(an archaic or historical term for a prison guard) minus(releases) “n”(symbol for “knight”, in chess notation).
14. Copper with unusual hobby almost rented small room (9)
CUBBYHOLE : CU(symbol for copper, the chemical element) plus(with) anagram of(unusual) HOBBY + last letter deleted from(almost) “let”(rented/leased out).
16. Any clue relying on solver taking initial characters? (8)
ACROSTIC : 1st letters, respectively, of(taking initial characters) “Any clue relying on solver taking initial characters”.
Answer: A word puzzle in which the initial letter of each solution to the clues, taken in order, form a word, phrase or the alphabet; and the latter helps in solving the clues.
17. Report of diamonds causes amazement in unsightly buildings (8)
EYESORES : Homophone of(Report of) [ “ice”(slang for diamonds, the precious stones) + “awes”(causes amazement/wonderment) ].
19. Lambasted extremely sarcastic, veteran journalist (7)
SCOLDED : 1st and last letters of(extremely) “sarcastic” + OLD(veteran/experienced) + ED(abbrev. for “editor”, a journalist).
20. Prison starts to rehabilitate extraordinarily rowdy troublemaker (7)
STIRRER : STIR(prison) + 1st letters, respectively, of(starts to) “rehabilitate extraordinarily rowdy”.
Defn: … who causes a stir/disturbance.
21. Grave-digger from Sweden crushing former heavyweight (6)
SEXTON : S(International Vehicle Registration code for Sweden) placed above(crushing, in a down clue) EX-(prefix signifying “former”/once) + TON(a unit of measure of weight, a heavy weight in this case).
Defn: … working for a church.
22. Helping Barbie, say, ring Papa (6)
DOLLOP : DOLL(an example of which/say is Barbie, representing an attractive young woman) + O(a ring-shaped letter) + P(letter represented by “Papa” in the phonetic alphabet).
Defn: A …, usually a blob of soft food.
25. Upper rate (5)
SPEED : Double defn: 1st: Slang for amphetamine, a stimulant drug or, informally, an upper; and 2nd: … of movement or operation.
Thanks scchua for the colourful blog, and Steerpike for an entertaining puzzle and pangram to boot. In “lowdown” there is another “w” to include (from the word “with”), just for completeness.
The odd letters trick in “camomile tea” is the longest I can recall seeing – truly impressive! It took me a while to break “eyesore” down as needed and I thought the rather indirect [r]ib[s] a bit of a stretch but otherwise nothing to scare the horses.
This was fun, thanks to Steerpike and scchua
A lot of this one had me stumped during the morning, but at lunchtime it opened up for me (I had been doing other things; I can’t spend all morning doing crosswords . . .) and TROJANS and EMILE ZOLA were my last in – I should’ve got these sooner – I mean, nothing else fits 11a, but so it goes. A good workout, and thanks to Steerpike and scchua.
Thanks Jack Of Few Trades. Blog corrected.
I’m not used to seeing ChAMOMILE TEA without the silent H, so I initially rejected it as not fitting until I had all the crossing letters. But now I’ve learned that the H-less version is apparently British. Which is weird, since normally the American spellings are the simpler ones. And like JOFT, I think that’s the longest answer I’ve seen clued with the alternate-letters device–very impressive.
Nice surfaces all round meant many ticks: SKETCHY, SNAG, STIRRER, LOWDOWN, ABOUT FACE, and TROJANS. I agree with JOFT@1 that CAMOMILE TEA was special.
Thanks Steerpike for a very enjoyable puzzle and thanks scchua for the blog
Loved acrostic and camomile tea. Thanks both!
Bin chicken? One seen twice today. I really enjoyed this.
Thanks Steerpike and scchua
I don’t think anyone has pointed out that the puzzle is a pangram.
Simon. Jack did @1.
Thank you all. I would add that in 10, a possible definition of “whosoever” is “anybody that” and should be underlined as such. This takes account of the otherwise awkward “that” in the clue.
Hovis @ 10 That’s the problem with skimming! 😉
(In my defence it’s been a trying day)