Times Jumbo 1117

No need to think of anything new to say by way of pre-amble, I can simply cut and paste from my last Jumbo blog, which said "Solved in just under 31 minutes, and usually I reckon anything under 35 on a Jumbo is about par for the course in terms of difficulty. Lots of nice clues, though." I don't know if it's intentional, but there seems to be a lot of consistency in Jumbos these days, and they're often the best puzzle of the week.

With Jumbos, which attract a far smaller audience than daily puzzles, I generally confine myself to discussion of answers which I think are a) less straightforward for inexperienced or non-UK based solvers, or b) especially elegant / questionable. In other words, unless it's an exceptionally interesting puzzle, the coverage is unlikely to be 100%; however, as always, if a particular clue is not discussed, please feel free to raise it in comments for explanation or discussion.

Across
1	CASSOULET - [SOUL(person) in CASE(amount of wine)] + Tons.
13	STANDARD GAUGE - (ANDGUARD)* in STAGE; the measurement of track width established by Stephenson and adopted by much of the world subsequently.
14	IMPORTUNE - IMPORT, UNE("one" in French).
15	ACADEME - A CADE, ME. Jack Cade, a leader of a popular revolt against Henry VI, appears a lot in crosswords.
16	IPSWICH - SW1 (postcode of the Victoria/Westminster area of London, including the Houses of Parliament) inside 1 P.C. kentisH. Nicely composed surface to disguise the town being in Suffolk, and nothing to do with London.
18	DEMONSTRATOR - DEMON'S, (ART)rev. TO Right. The sort of car dealers keep for test drives before selling on as nearly-new models.
20	TRANSACTOR - TRAINS ACTOR is the description of what a tutor at RADA does, take away Industry.
23	OSTIA - O/S (ordinary seaman), Tavern In Ancient; the port of Rome in classical times.
24	GINGER ALE - GINGER (="spirit", more usually used as a verb, as in "ginger someone up"), "AIL". Nothing to do with gin, as I eventually worked out.
25	SADDOES - (ODD in SEAS)all rev.
28	CHEESE STRAW - (EASTER,eggS)* in CHEW.
30	PURITANICAL - [RITA in PUN], 1 CALL. Rita as in the heroine of Willy Russell's Educating Rita
34	INCUBUS - U=universal, the cinema certificate indicating a feature is open to all, placed inside IN CUBS.
38	FACER - Feydeau wrote notable FARCEs, move the Run to the end. A slightly old-fashioned term; one can imagine Bertie Wooster saying "Well, Jeeves, this is a bit of a facer, and no mistake".
39	GILLINGHAM - ILL in GINGHAM; as the clue suggests, a small town in Kent which would probably be utterly anonymous if it didn't appear in the classified football results every Saturday; trivia buffs will already know it's the only professional team in the county.
46	IMITATE - fIlM, (TATI)rev., English. In crossword setting circles, Jacques Tati is as popular a director as Cade is a rebel.
47	RIOT ACT - The World Cup was held in Brazil, so it's RIO, Territorial Army, CourT.
50	SIEGFRIED LINE - SIEGFRIED (Sassoon), LINE. Sassoon would have known the original Siegfried Line, and the surface reads well, even if the poet's writings said the very opposite.
53	DOORMAT - (ROOD)rev., MATe
54	PENITENCE - UNITE in PENCE(=coppers).
Down
1	COSTARD - STARving in COD; an old term for an apple.
2	STABAT MATER - (BATS)rev., AT MASTER without the Second. A very old hymn indeed.
6	DRUGSTORE - Discount RUGS TORE. Lift and separate required to stop thinking of it as Poundland.
7	FOETID - FOE, sergeanT, I.D. Nice use of the two meanings of "rank" to produce another fine surface.
8	NEITHER HERE NOR THERE - Not sure I really understand this - I can see that it means "not important", but not "in the middle of nowhere", which I think could easily be covered by "there", if not "here". Am I missing something, or just being over-analytical?
11	ROUGE ET NOIR - (IURGEONE)*, Resume. Anagrams are much less obvious when they turn out to be in a foreign language.
16	IT AIN'T NECESSARILY SO - another way to express the meaning of the song from Porgy and Bess.
21	ROSE-WATER - ROSE(wine), With (TEA)* Right. Not a term I was familiar with, but easy enough from wordplay; as rose-water is light and delicate, so it can be used to describe people who are the same.
22	MADCAP - [A D.C.] in MAP.
23	OFFSPRING - If you were off spring, you might well be ready for summer to arrive...
25	SUSTAIN - STAID in The SUN.
27	TALENT - TALE(=parable), N.T. Lovely all-in-one clue as there is the well-known Parable of the Talents in the gospels of Matthew and Luke. My COD for that elegant incorporation.
29	SCOFFER - COFFEE in SisteR.
33	INCANTATION - INCA (old South American) [Tourist in NATION].
35	BLISTERED - LISTER in BED; Sir Joseph Lister, pioneering surgeon of the Victorian age.
40	GARBLED - GARBO LED.
44	DIM SUM - DIM "SOME".
45	CINNA ="SINNER"; one of Caesar's assassins, and as with Cade and Tati, a most popular figure in Crosswordland (he cropped up again in the daily puzzle only last week, I think).
48	ON DIT - "on dit" meaning rumour seemed quite familiar, and a quick search shows it appearing in a blog I wrote in January, so it's nice to know that these things do sometimes stick. The wordplay is ON(=about), EDITH, where unclothed (or uncloted as the online version of the clue unhelpfully has it) means "losing the first and last letters". Plus Edith Piaf being French adds polish to the surface in a way which is characteristic of the whole puzzle.