Stroke Horizontally by Henry

A rather straightforward puzzle acknowledging the 25th anniversary of the first performance of Andrew Lloyd Webber's show "Cats". This was indicated by the misprinted letters from across clues spelling out "Thomas Stearns Eliot", whose poems formed the libretto, and those from down clues spelling out "Andrew Lloyd Webber". Once T.S.Eliot appeared early on, the theme was revealed. Three clues led to characterizations from the show, and in these cases the cats' names were to be entered instead, thus:

17 GLAMOUR à Grizabella the glamour cat

34 THEATRE à Gus the theatre cat

1d RAILWAY à Skimleshanks the railway cat

The "naming" and "ad-dressing" (entered WITH the hyphen) of cats were unclued entries, as was "Memory", the title of the show's best-known song. For 16 and 24, Gregson entered CAST and ACTS as anagrams of CATS that seemed more-or-less thematic, though he couldn't quite reconcile those entries with the preamble's directions. Finally, the name of "Macavity", the cat who wasn't there, was to be found and highlighted in pairs of symmetrically placed cells. (For once, Gregson was able to forgo checking in ODQ for a referenced quotation).

The cluing was fair but there were plenty of tortured surfaces, and rather a preponderance of punctuation. Some of these clues were rather more pleased with themselves than they had any right to be.

Across
1 Problem's heard[t] inside what might be a torpedo that can be entered for inspection (11)
SUBMISSIBLE (B (middle letter of PROBLEM) inside SUB MISSILE)
10 Cambodia: incorrect t[h]erm for Pol Pot (5)
KHMER (K (IVR Cambodia) + jumbler HERM)
11 New money invested in th[o]e annuity scheme with dwindling membership (7)
TONTINE (N(ew) + TIN (money) inside TOE)
12 Terrible w[m]ail by a creeping, bloodthirsty witch? (5)
LAMIA (Jumble MAIL + A)
13 Te[a]lly needs electricity supply and flex (6)
ACCORD (AC + CORD)
15 H[s]ome team a tad dull (3)
MAT (Hidden in teaM A Tad)
17 Girl lov[s]ing Irish sweetheart's magnetism (10)
GLAMOUR (GIRL minus IR(ish) + AMOUR)
18 Poll of Conservatives showing stark[t] switching to Liberal (4)
LORY (TORY with L(iberal) replacing first letter)
20 I'm about to complete around one. Exemplarily, I'm all p[e]ars! (5)
IDIOM (I (one) inside DO, inside I'M)
Not a very clear definition.
21 Fli[a]t to the country when it gets dark? (4)
EVEN (Two meanings)
There doesn't seem much justification for the question mark.
23 See preamble (4)
CATS
25 Took c[r]are holding lady's fingers (4)
OKRA (Hidden inside toOK RAre)
26 Awful sing[n]ing's found here -- thus ancient cathedral lacks what comes first in England (5)
SODOM (SO + DOME minus E)
A good definition, whose present tense is justified since Chambers defines Sodom as any place of depravity.
30 Old man's p[s]ale? This provides air... (4)
VENT (Twop meanings)
31 ...A thin man[e] suffers, I see. Invigorating medicine? (1)
HAEMATINIC (Jumble A THIN MAE + IC)
Another unnecessary question mark.
34 Royal Opera House, for example; alter the dancing after Rambert is no more (3)
THEATRE (Jumble ALTER THE minus R(ambert))
35 See preamble (6)
NAMING
36 Mad cook ran[i]ted endlessly (5)
IRATE (Jumble RAITED minus last letter)
37 Toll includes five English, showing what Scottish pl[o]under may do (7)
KNEVELL (V (five) + E(nglish) inside KNELL)
38 Celtic man is sm[t]art to reverse inside past nos two and three of Rangers (5)
BRYAN (R (first letter of REVERSE) inside BY (= past) + AN (second and third letters of RANGERS)
39 See preamble (11, hyphenated)
AD-DRESSING

Down
1 NY lawcourt is able to be distracted, missing terribly subtle con tri[a]ck (13)
RAILWAY (Jumble NY LAWCOURT IS ABLE minus SUBTLE CON)
Cavalryman up[n] around top of hill overlooking US city (5)
UHLAN (H (first letter of HILL) + LA (Los Angeles) inside UN)
3 See preamble (6)
MEMORY (Overwrought show tune)
4 Inflamed judge's hear[d]ing of incentives for starting cocaine (6)
IRITIC (CRITIC with I (first letter of INCENTIVES) replacing first letter)
5 Lacking guts, soft soldier doesn't want cold. D[R]ubai division, perhaps? (6)
STANZA (S(of)T + ANZAC minus C(old)
Rubai is a Persian verse.
6 Devils having some si[e]x prime characters in impiety, nefariousness, corruption, ugliness, brazenness and iniquity (6)
INCUBI (First letters of IMPIETY, NEFARIOUSNESS, etc)
Blatantly obvious wordplay.
7 Blair? Avoids Europe primarily and associates with US president, as one who's frightful pos[w]er? (8)
LIONLIKE (LIONEL (Blair) minus E + IKE (Eisenhower))
8 Record horrible b[l]oner (5)
ENROL (Anag. LONER)
9 Gods celebrate about diversion of River Dee northwards -- making less like W[L]ear? (13)
DEDRAMATISING (TAMAR (river) + D reversed inside DEI + SING)
14 Belief rocked badly when kilt[o] is lifted (5)
CREDO (Jumble ROCKED minus K(ilo))
16 See preamble (4)
CAST
19 Did bus[y] back out of McDonald's yard? Judge goes into it (8)
REDEEMED (DEEM inside REED (Scottish yard)
22 Refreshing mood when l[d]aughter's let out in Greek provinces (5)
NOMOI (Jumble MOOD IN minus D(aughter))
24 See preamble (4)
ACTS
27 Playwright's denied a good talking p[w]art to one drunk by 7? (6)
MAINED (I (one) inside MANED (i.e. lionlike))
"Main" is a Shakespearean form of "maim", making this a good oblique definition.
28 Person enhancing intelligence through sex[e]ing up succeeded with one very dodgy lie (6)
VISILE (Jumble I (one) + V(ery) + S(uccessful) + LIE)
29 Rod[b]in's sculpted surrounds for Poets' Corner (6)
INORBS (Anag. ROBINS)
30 Devil's enemies presumably find six possible d[b]angers (6)
VICARS (VI (six) + CARS)
32 Pair from Andalusia with anecdotes about fruit from Gra[e]nada? (5)
ANANA (AN (first two letters of ANDALUSIA) + ANA (anecdotes))
33 Pel[r]t old girl who sounds like a cat (5)
QUEAN (Homophone QUEEN)