Thanks to Aardvark for this morning’s challenge.
An enjoyable and overall fair puzzle. Some tricky bits, but nothing too obscure in my opinion, although I did need to check a few things. Many thanks to Aardvark!

ACROSS
1. Part of church painting rebuffed before new month (8)
TRANSEPT
ART< (painting, <rebuffed) before N (new) + SEPT (month)
5. Couple in centre of Brecon retreat for cake (6)
ECLAIR
[Br]EC[on] (couple in centre of) + LAIR (retreat)
9. I’m surprised daughter embroidered your fabric (8)
CORDUROY
COR (I’m surprised) + D (daughter) + (YOUR)* (*embroidered)
10. Working member of staff readily available (2,4)
ON HAND
ON (working) + HAND (member of staff)
12. Philosopher starts to analyse rhymes TS Eliot constructed (9)
ARISTOTLE
A[nalyse] R[hymes] (starts to) + (TS ELIOT)* (*constructed)
13. Sponge the sheltered side with cold water, then hot (5)
LEECH
LEE (the sheltered side) with C (cold water) then H (hot)
14. Prison disturbance (4)
STIR
16. One fights old PM endlessly dividing Britain (7)
BATTLER
ATTLE[e] (old PM, endlessly) dividing BR (Britain)
19. Bone from bird used in exercise at school? (7)
STERNUM
TERN (bird) used in SUM (exercise at school)
21. Declare it hurts, sitting on collection of books (4)
AVOW
OW (it hurts) sitting on AV (collection of books, Authorised Version biblically)
24. Swimmer in tropics leaves around a pair of trunks (5)
TETRA
TEA (leaves) around TR[unks] (pair of)
25. Garden of Eden exhibit’s guarded by special rails (7-2)
SHANGRI-LA
HANG (exhibit) guarded by (RAILS)* (*special)
27. Insect one hears defacing small branch (6)
EARWIG
EAR (one hears) defacing (removing face) [t]WIG (small branch)
28. Flimsy edging of villa, full of holes (8)
VAPOROUS
V[ill]A (edging of) + POROUS (full of holes)
29. They go out, quietly leaving punt on river (6)
EXEUNT
[p]UNT (P (quietly) leaving) on EXE (river)
30. Vehicle’s parked outside residence of retiring nurses (5,3)
CARES FOR
CAR (vehicle) parked outside RES (residence) + OF< (<retiring)
DOWN
1. Signalling system gets twitching feline back (3-3)
TIC-TAC
TIC (twitching) + TAC< (feline, <back)
2. Dexterous lady from city repeatedly taking centre-stage (6)
ADROIT
[l]AD[y] [f]RO[m] [c]IT[y] (repeatedly taking centre stage)
3. Having spent millions, US president’s backing jet (5)
SPURT
TRU[m]P’S< (US president’s, having spent M (millions), <backing)
4. University official trained on cold peak (7)
PROCTOR
PRO (trained) on C (cold) + TOR (peak)
6. Nick, perhaps bitter, upset extreme artist (9)
CANALETTO
CAN (nick) + ALE (bitter perhaps) + OTT< (extreme, <upset)
7. Mailman regularly maintains place for sorting, unaccompanied (1,7)
A CAPELLA
[M]A[i]L[m]A[n] (regularly) maintains (PLACE)* (*for sorting)
8. Anarchist once studied, we hear – is it kept buttoned up? (3,5)
RED SHIRT
“READ” (once studied, “we hear”) + SHIRT (is it kept buttoned up?)
11. Basil maybe the latest to scrub beneath that boat (4)
HERB
[Scru]B (latest to) beneath HER (that boat)
15. Shade covers short eccentric Scotsman, resident in Africa (9)
TANZANIAN
TAN (shade) covers ZAN[y] (eccentric, short) + IAN (Scotsman)
17. Wonder about model soldiers, so to speak (2,2,4)
AS IT WERE
AWE (wonder) about SIT (model) + RE (soldiers)
18. Ancient coin having unusual crest, found in Durham, say (8)
SESTERCE
(CREST)* (*unusual) found in SEE (Durham, say)
20. Smell comes from river alongside motorway (4)
MUSK
USK (river) alongside M (motorway)
21. Popular type of novel, whichever way you look at it (3,4)
AGA SAGA
AGA SAGA (whichever way you look at it: clued only by the fact that it is a palindrome)
22. Informer might pronounce this refuse centre unavailable (3-3)
TIP OFF
TIP (refuse centre) + OFF (unavailable)
23. Rope wife into trading share (6)
HAWSER
W (wife) into (SHARE)* (*trading)
26. Sunbathing? Ultimately, not a thing that’s worn (5)
GLOVE
[Sunbathin]G (ultimately) + LOVE (not a thing)
I was unable to determine in what context RED SHIRT meant “anarchist”? I assume that there is a history lesson there somewhere. I do not think I have seen the device used to clue ADROIT before, i.e., that particular variant of the hidden word. I was unfamiliar with AGA SAGA, but it was findable, if not exactly guessable. There are several (presumably) unintentional ninas in the completed grid. If they amount to anything, I don’t see it, although I occasionally wonder whether an indelicate one might sometime escape the editor’s notice. Fine job on the blog.
Further to that: It would seem theoretically possible that a puzzle could be constructed in which all of the unchecked lights also spelled words, like an exploded version of an American crossword. Has anyone ever seen such a grid?
A good respite from quite a few unusual words seen in several recent crosswords. The only words I had difficulty in bringing to mind were the crossing ‘Swimmer in tropics’ at 24a and the ‘Ancient coin’ at 18d. I hadn’t come across PRO for ‘trained’ at 4d before and still only sort of get it. I liked AGA SAGA (despite the loose definition) and the surface of 6d misleadingly suggesting CANALETTO was an ‘extreme artist’.
Exactly the same comments as Cineraria @1 & 2 about the possibly intended words hidden in the grid. They don’t add up to anything for me but perhaps I’m missing something. I’ve never seen a grid in which all of the unchecked letters spelled words.
I thought RED SHIRT (? the def is ‘Anarchist once’) would refer to a member of a left-wing military group (and maybe it does), but looking it up on Wikipedia just now, I was surprised it to see it also referred to members of a white supremacist organisation in the southern states of the US in the latter part of the 19th century.
Thanks to Aardvark and Oriel
Thanks for the blog, I really enjoyed this . Lots of clues to admire , agree with Cineraria about the ADROIT centre stage, TANZANIAN was very nice, GLOVE simple and effective.
Perhaps the most famous RED SHIRTS were the followers of Garibaldi but they were not really anarchists.
Hi Wordplodder@3,
Can you highlight some of the words you are referring to, formed by unchecked letters? [ I was unfamiliar with “unches” so did look it up but I am not able to see how all of them spell words.
Thanks in advance for the education.
TL
Turbolegs@5: Well, the grid says RACE CHAPS TORE AT ZUG, which looks like a bad cryptic clue itself, and I also see TORCH, TEA, and INCEL.
Thanks Aardvark for many fine clues including SHANGRI-LA, EARWIG, A CAPELLA, HERB, AS IT WERE, and GLOVE. I needed a word finder for AGA SAGA and the clever ADROIT. I believe I’ve seen the uncommon device used in ADROIT once or twice before. If anyone has (or could) produce a crossword where the unchecked squares read as words it would be Monk or Basilisk/Serpent. Thanks Turbolegs for the blog.
A fairly gentle stroll with no real problems, although we couldn’t see the parsing of ADROIT, and A CAPELLA went in from definition, enumeration and crossing letters without bothering to parse it. We thought of the RED SHIRTS as Garibaldi’s followers without thinking if they were really anarchists.
Thanks, Aardvark and Oriel.
Cineraria@5 – Thanks for the inputs.
Tony@7 – No doubt you meant your thanks for Oriel who blogged.
Regards,
TL