A fun start to the day from Io.
I had most of this parsed quite early this morning, and then, as usual, needed extra time to mull over some of the trickier clues. Many thanks to Io for the enjoyable challenge.

LET JAG (nice hire car, from Spooner)
END ASHES (what winning run will do in series down under, cricket reference)
P (dull, music) + OILING (exertion) that keeps OT, B (books, Old Testament, books) to the fore
There may be a more elegant parsing of this, so do comment if you have a different view
“ADZE” (something cutting, “from mike”)
O (nothing) in BAR (apart from)
REMINDERS (memoranda), + [memorand]A (the last of which) is penetrating
(SUBS (membership) accepting ALLY (associate))< (<reviewed)
[t]HE (principal leaves) + L (lecturer) with PER (an)
ON (about) + [th]E (last of) repeats (i.e. duplicate the solution)
SLY (surreptitious) stealing LIGHT (land)
Holding GEN< (information, <back); ABATING (decrease)
Double definition
A[l]C[a]T[r]A[z] (logged on and off)
(TA[x]I CROSSED)* (*barking, leaving X (by))
COEN (filmmaker) has GALL< (cheek, <on counter) to inject
([trawlerma]N IS HAD)* (*taking a beating)
E-CON (online fraud) + O[f] (taking half) + MY (the writer’s)
(BILL [of f]ARE)* (*ordered, OFF off (this))
HG< (mercury, <rising) + [spo]I[led] (essentially)
(MENSA GI[ft] (out of FT))* (*oddly make)
(G,G (two Germans) + FIND + HIT GO (22s clue))* (*complicated)
[di]SC AND AL[bum] (covers)
END [h]ORSE (the last [h]ack in the race)
(D[uke] (‘s head) + LOUNGE BAR)* (*moving) around B (barrels)
(OC (commander) + CUBAN (Castro perhaps))< (<upset)
[disc]OVER ALL[usions] (hiding)
TILT (list) extends SO (considerably) + [Pali]N (‘s close)
HE’S (this chap’s) + (SIN (wrong) about A)
NO 1< (what she wears, <from the ground); LESS (without) trousers
Hannah Hampton is the goalkeeper for the Lionesses, England’s female football team, traditionally wearing the ‘1’ jersey
DNA< (double helix, <up)
Tough! Only six questions this time (!), one being which particular Coen was intended in 26a: Ethan or Joel? I liked the clue though.
Some unknowns I could parse ( more used to ‘ghee’, for instance) but for a handful others (the goalkeeping Lioness, for instance), I had to come here.
Other picks included LIBERAL, DOGFIGHTING (for the extra layer) and RUBBED ALONG.
Always good to learn new things so thanks, Io, and Oriel for a much-needed blog.
POTBOILING – I took as PO TOILING keeping the first letter of Books .
Thanks for the blog , not an easy task but I have seen a lot worse from IO , perhaps quite an easy start for once and I think some of the definitions were pretty friendly .
9. Almost my PB for IO.
I can only have the deepest admiration for anyone solving this, including our blogger. Much too hard for me and, I suspect, many others; I managed just 7 clues. Best for mere mortals to leave Io alone.
Loved the puzzle. Superb blog.
Thanks Io and Oriel.
My top picks: JET LAG, LIONESS, POTBOILING, ADDS, ABNEGATING, STILTON,
OSTRACISED and ECONOMY.
POTBOILING
Had the same parse as Roz.
LIBERAL – I had as a compound anagram . Bill of fare = (ordered ) OFF LIBERAL ( this ) .
You may be saying this in the blog , I know you need to be brief .
I agree with Roz@2 on POTBOILER. I could not quite resolve STILTON, so thanks for explaining. (I got stuck on an anagram of LIST + ???, which does not work.) I found this relatively approachable, for an Io, with perhaps LIONESS requiring the most obscure extra knowledge to solve. No nina or theme?
I got 19 answers today, an unheard of feat where Io is concerned, but although I should feel pleased with myself, I can’t help finding his puzzles a terrible slog. I admire those who find them “fun” or “entertaining.”
When it’s Io I get a lot of answers from simply trying to find the definitions and ignoring the wordplay, but today that wasn’t helped by never having heard of Ms Hampton, ONE ONE or EN DASHES. I had guessed EX DASHES, (dash in exes) in the hope that it was the name of some unwatched and peculiarly-named Australian soap opera. I forgot my rule that if an explanation sounds ridiculous, the answer’s likely to be wrong.
I liked ENDORSE.