3950 Wot, No Lines? By Charybdis

With a grid that resembled a pattern of bricks, Charybdis amusingly incorporated the theme of writing on a wall. There were 7 unclued entries – 1 TEKEL UPHARSIN 15 ANAGRAMS 17 WRITING ON THE WALL 22 GRAFFITI 24 CHAD 40 MENE (doing double duty) 48 KILROY WAS HERE. Extra letters in the wordplay of clues gave the message – HIGHLIGHT FIFTEEN DOWN AND SIX LETTERS ON A MAJOR DIAGONAL. So the puzzle ended in a joke with the highlighted ANAGRAMS LURE OK!
The phrase “Mene, mene, tekel upharsin” is from the Bible and Charybdis’s clue (as part of 20 5 25) caused Gregson some anxiety. Only the first number refers to the crossword – Daniel chap. 5 v. 25.

Extra letters in wordplay not entered in the grid are shown in brackets.

10-letter
36 I urge, tag the wild cat
EGURGITATE anag. I urge tag t(h)e
9-letter
3 A feller's flirtation with the high sea
LUMBERMAN LUMBER (flirtation) + MA(I)N
8-letter
12 That woman's no good, putting in appearance as young long-legged bird
HERNSHAW HER + N(G) + SHAW (appearance)
13 Woman including international number in short cheerful shanty
SHIELING (a rough hut) I in SHE + N in LIG(H) (shortened LIGHT=cheerful)
34 Author, starting with theft of gold, tells capers - a yarn-spinner
THROSTLE anag. (au)thor (less gold Au) + TE(L)LS
47 A set of two lines on railway are accepted to be this
PARALLEL PA(I)R + A (are) + LL (lines) + EL (railway)
7-letter
2 Bad week in which to invest pence and pound as Guinea's old money
EKPWELE P in anag. WEEK + L (pound) + E (G) (eg=as)
6 Medic finally interrupting to turn to right leg perhaps and shin
UPCLIMB C (last letter of Medic) in (H)UP + LIMB
24 Cloudy ethanol - when drunk it can stunt growth
CHALONE C (cloudy) + anag. E(T)HANOL
25 Descartes' conclusion?: A fragment of bard's handwriting - Shakespeare, perhaps?
IAMBIST I AM (conclusion of Descartes’ I think therefore...) + B + (F)IST
32 Motorbikes running or crashing into antelope
STEMBOK anag. MOTORB(I)KES less OR
33 Parent adopting not one - a second
ANOTHER NO in (F)ATHER
37 Okra and sesame can give you an ulcer
GUMBOIL GUMBO + (T)IL

6-letter
4 With mess around anger's rising - it could be pussy!
HARISH IR(E) (rev.) in HASH Puss is a hare in coursing or hunting.
5 Report pursuing whale's source of strength
SINEWS S(E)I + NEWS
8 Three in one manage about one in ten
TRIUNE I in RUN (manage) in TE(N)
9 Clean up cow's bottom
NEATEN NEAT (cow) + EN(D)
14 Cavalryman, one making advances astride of colt
LANCER C in L(O)ANER
17 Deserter's last seen in Great War - declined to return - and works as a clerk
WRITES R (last letter of Deserter) in W(W)I + SET (rev.)
20 "God's absolute law in the Beginning," a cardinal interjected. He means: "the lord is judge"
DANIEL A NI(N)E (cardinal number) in D (God) + AL (first letters of Absolute Law) Chambers explains DANIEL as (Heb.) the Lord is Judge)
23 Aristocratic bird, one that turned into a swan
TITLED TIT(a bird) + LED(A)
30 Branch has 20 per cent off fashionable end of line candle
BOUGIE BOUGH (less H) + I(N) + E (last letter of LINE)
31 Old cracker finds link with reduced security
BONBON BON(D) + BOND less last letter
32 On return lightly cleans round gold blanket (a rarity)
STROUD OR (gold) in DU(S)TS reversed
35 Sport a new array of tiles - swish!
RUSTLE RU (Rugby Union) + anag. T(I)LES
38 Annual income - extra oddly going astray reveals letter
RENTER RENTE + anag. E(X)TRA less odd letters
39 Caddy: "Els's first to play shot"
TEAPOY anag E + TO P(L)AY

5-letter
4 One who intensely dislikes American shooter
HATER H(E)ATER
7 Wipe motorcycle tank pinions
CLEAN Hidden motorcycle (T)ank
10 Like the country set full of unwanted growth
WEEDY (T)WEEDY
16 Metal fragments heat by rubbing top of flywheel
CHAFF CHAF(E) + F (first letter of FLYWHEEL)
18 Had a cuppa, having a drop with Edmund
TEAED TEA(R) + ED
27 Topless girl showed the way and lived like Crusoe
ISLED (S)IS + LED
28 May for instance satellite television harm in early stages?
MONTH MO(O)N + first letters TH
31 Split's possible constituent finally takes time to supplant a military district
BANAT BANA(N)A constituent of Banana Split! replacing A with T (time)
42 Fruit's in equal quantities over headland
NARAS (A)NA + RAS
43 It swam around central part of ship
WAIST anag. IT SWA(M)
44 Everything on earth is taken by the taxman - that's not so good
ILLER (A)LL + E (earth) in IR (Inland Revenue)
45 Jester's eccentric conduct
STEER anag. (J)ESTER
46 This fencing pass is not to be beaten - take note
BOTTE anag. N(O)T TO BE less N (note)

4-letter
11 A moisture extractor, not a stain remover!
DYER D(R)YER
12 That girl's divine in company of beasts
HERD HER + D(D)
22 Bergman's no new framework for theatre
GRID (I)NGRID (Bergman) less N (new)
26 Smear tar over most of bait
BLUR (A)B (seaman or tar) + LUR
28 Knock back G&T and whisky
MALT LAM rev. + (G)T
29 "Goodies kill hero", you blub - final parts reveal twisted yarn
SLUB Last letters GoodieS kilL her(O)", yoU bluB

3-letter
19 Cash on tap? There's nothing odd, I've got it!
AHA even letters – cAsH o(N) tAp
21 Bloodless to over halfway? Macbeth's not so
NAE (A)NAE[mic]
41 Scrawny bear
EAN 2 definitions (L)EAN