PETO provides Monday's puzzle…
A solid start to the week. Plenty of neat clues with some great surfaces.
Thanks PETO!

ACROSS
1. Giuliani not quite taken in by former VP’s circumspection (8)
PRUDENCE
RUD[i] (Giuliani, not quite) taken in by PENCE (former VP)
5. Reprimand helping to make Oscar petrified (6)
CARPET
[os]CAR PET[rified] (helping to make)
9. Head of investigation looking into cruel DI’s broken rib (8)
RIDICULE
I[nvestigation] (head of) looking into (CRUEL DI)* (*broken)
10. Author of legal document meeting Nehru regularly (6)
WRITER
WRIT (legal document) meeting [n]E[h]R[u] (regularly)
12. Record single about maintaining resistance (5)
ENROL
(LONE)< (single, <about) maintaining R (resistance)
13. Highly specialised subjects in essentially impressive books by Heather (9)
ESOTERICA
[impr]ES[sive] (essentially) + OT (books) by ERICA (heather)
14. Humble clergyman touring Maine (6)
DEMEAN
DEAN (clergyman) touring ME (Maine)
16. Take up space with orthopedic device (7)
EMBRACE
EM (space) with BRACE (orthopedic device)
19. Finished with Henry during a low point (7)
THROUGH
H (Henry) during TROUGH (a low point)
21. Nasty smell coming from piece of salty fish (6)
STENCH
S[alty] (piece of) + TENCH (fish)
23. Canaries flying around island cause a commotion (5,4)
RAISE CAIN
(CANARIES)* (*flying) around I (island)
25. Amusing for Latin master in retirement (5)
DROLL
(L (Latin) + LORD (master))< (<in retirement)
26. Incarnation of Virginia stabbing key informer from behind (6)
AVATAR
VA (Virginia) stabbing (A (key) + (RAT)< (informer, <from behind))
27. Being king in Niger and capital of Gabon somehow (8)
REIGNING
(IN NIGER and G[abon] (capital of))* (*somehow)
28. Worry throughout attempt to create international agreement (6)
TREATY
EAT (worry) throughout TRY (attempt)
29. Rebel overwhelmed by negative effect of Baudelaire perhaps (8)
DECADENT
CADE (rebel, Jack Cade) overwhelmed by DENT (negative effect)
DOWN
1. Left with concern Verdi oddly dismissed (6)
PARTED
PART (concern) + [v]E[r]D[i] (oddly dismissed)
2. Hidden behind Don’s vest maybe (9)
UNDERWEAR
UNDER (hidden behind) + WEAR (don)
3. Be better without the Spanish clubs entering (5)
EXCEL
(EX (without) + EL (the, Spanish)), C (clubs) entering
4. Pass by fellow hugging English girl in Cork (7)
COLLEEN
COL (pass) by LEN (fellow) hugging E (English)
6. A largely new island retreat is to one’s liking (9)
AGREEABLE
A + GREE[n] (new, largely) + (ELBA)< (island, <retreat)
7. Place Italian uplifted with cherubic representations (5)
PUTTI
PUT (place) + (IT)< (Italian, <uplifted)
8. Cow getting most of the clover finally polished off (8)
THREATEN
TH[e] (most of) + [clove]R (finally) + EATEN (polished off)
11. European author’s gripping last novel (4)
POLE
POE (author) gripping [nove]L (last)
15. In high spirits as former partner and unionist exchange banter (9)
EXUBERANT
EX (former partner) and U (unionist) + (BANTER)* (*exchange)
17. Recluse finding source of security at internet location? Not initially (9)
ANCHORITE
ANCHOR (source of security) + [s]ITE (internet location, not initially)
18. Beginning to accept Norm in the main role (4,4)
STAR PART
START (beginning) to accept PAR (norm)
20. Energy obtained eating a nut (4)
HEAD
E (energy), HAD (obtained) eating
21. Seeing that about being genuine (7)
SINCERE
SINCE (seeing that) + RE (about)
22. Small deposits ultimately worthless (6)
SLIGHT
[deposit]S (ultimately) + LIGHT (worthless)
24. Furious when letter on Religious Instruction is returned (5)
IRATE
(ETA (letter) on RI (religious instruction))< (<returned)
25. Belief in an idol brought up by mum (5)
DOGMA
(GOD)< (idol, <brought up) by MA (mum)
Thanks Peto and Teacow!
Agree with Teacow regarding ‘neat clues and great surfaces’.
My faves: PRUDENCE, RAISE CAIN and AGREEABLE.
Could someone please explain how ‘part’ = ‘concern’ in 1d?
Thanks Peto and Teacow
1dn: Collins 2023 gives us (as nouns):
“part 6 a person’s proper role or duty”; and
“concern 3 something that affects or is of importance to a person; affair; business”.
I took it on trust when solving, but I think that does it, reinforced (under part) by “13 for one’s part as far as one is concerned”.
What KVa@1 wrote
PB@3 Yes, I agree that this is probably what was in the setter’s mind, but I think it too much of a stretch to pray this in aid as a justification for using “concern” as a synonym for “part”. I’d be prepared to accept it if the two words could simply be interchanged in a meaningful sentence. Perhaps someone can supply one?
PARTED
part
The Chambers mobile app lists 28 meanings under ‘part’ noun. At No 13 is ‘Concern’.
A sample sentence? Waiting to be educated.
I too struggled with Parted, but couldn’t think of anything else to fit.
Thanks for explaining Decadent. I recall now come across Cade previously, but I forgot it here. After a lot of head scratching, Decadent was the only word I could see which would fit. Anchorite was a new word, which required the help of a Thesaurus.
Putti also new to me, but easy from word play.
Thanks to all; especially for the clear blog.
I found this at the slightly easier end of the Peto spectrum
As for Part and Concern, maybe:
“It’s not my [concern / part] to clear up the rubbish after the children”.
Got almost all of it, though without understanding some of the parsings. Failed on 20dn where the misleading word order suggested the definition was ‘energy’ leaqing to ann insertion of ‘a’ inro ‘het’ which didn’t make sense.
But thanks, Peto and Teacow.
In addition to echoing what KVA@1 wrote, I would also like to echo what Moly@7 wrote – with the exception that I remembered CADE from a previous crossword without the head scratching.