Across
Put steps outside at home with men planning (9)
I haven't cracked this one yet — but Fifteensquared have:
OR (=men, i.e. other ranks) + [IN (=at home) in DANCE (=steps)]
Scottish John stops Pilot Officer in quiet passage (5)
I haven't cracked this one yet — but Fifteensquared have:
IAN (=Scottish John, i.e. a Scottish version of the name Ian) in PO (=Pilot Officer); a piano is a soft, “quiet passage” in music
Good and bad to host initially riotous quiz (5)
I haven't cracked this one yet — but Fifteensquared have:
R <iotous> (“initially” means first letter only) in [G (=good) + ILL (=bad)]; to grill someone is to quiz them, asks lots of questions
17d
(and 17 Down) Does this foresee terrible cost, recession and a war? (5,4,8)
Two for one for example in Bury (7)
I haven't cracked this one yet — but Fifteensquared have:
E.G. (=for example) in INTER (=bury, place in ground); an integer is a positive whole number, of which two is an example, hence “two for one”
Who might steal eggs — and slowly cook them? (7)
I haven't cracked this one yet — but Fifteensquared have:
Cryptically, a poacher of eggs would “slowly cook them”; a poacher is someone who might steal e.g. birds’ eggs
Ascetic at last departing for Ruhr location (5)
I haven't cracked this one yet — but Fifteensquared have:
ESSEN <e> (=an ascetic, from a small Jewish fraternity; “at last departing” means last letter is dropped); Essen is a city in the Ruhr region of Germany
Study Hesiod's conclusion in French (3)
I haven't cracked this one yet — but Fifteensquared have:
<hesio> D (“conclusion” means last letter only) + EN (=in French, i.e. the French word for in )
One donning Great King's spun garment (5)
Old Greek university plugging dissertations (7)
Cosmonaut, wildly enthusiastic, to call shortly (7)
I haven't cracked this one yet — but Fifteensquared have:
GAGA (=wildly enthusiastic, crazy about) + RIN <g> (=to call; “shortly” indicates last letter is dropped); the reference is to Soviet pilot and cosmonaut Yuri Gagarin (1934-68)
Romanian dictator stops hoarding uranium and copper (9)
I haven't cracked this one yet — but Fifteensquared have:
[U (=uranium, i.e. chemical symbol) in CEASES (=stops, ends)] + CU (=copper, i.e. chemical symbol); the reference is to Romanian dictator Nicolae Ceasescu (1918-89)
See 1 Down
Be patronising towards women denied sons (5)
I haven't cracked this one yet — but Fifteensquared have:
<s> EXIST (=patronising towards women); “denied sons (=S)” means letter “s” is dropped
Book in Spanish English twice revised (9)
I haven't cracked this one yet — but Fifteensquared have:
*(SPANISH + E (=English) + E (=English)); “ English (=E) twice” means that 2 x E are added to the anagram, indicated by “revised”; the reference is to the Epistle to the Ephesians, attributed to St Paul, in the New Testament
Down
26a
(and 26 Across) Greeting from one again and again denied preferment? (4,4,2,3)
Person misusing horse? Put on an extra court (6)
I haven't cracked this one yet — but Fifteensquared have:
ADD (=put on) + I (=an extra) + CT (=court, in addresses); the “horse” of the definition is a slang word for heroin
Doctor Galen with niece: not Grace? (10)
Person with assured belief Arkwright heard? (6)
I haven't cracked this one yet — but Fifteensquared have:
Homophone (“heard”) of “Noah (= “Arkwright”, i.e. the builder of the ark in the Old Testament)”
Easy opportunity to bag stray reptile (8)
I haven't cracked this one yet — but Fifteensquared have:
ERR (=stray, wander off course) in TAP-IN (=easy opportunity to bag, in sport)
Kitty after second little bit (4)
Revolutionary husband taking place in battle (8)
I haven't cracked this one yet — but Fifteensquared have:
MARAT (=revolutionary, i.e. Jean-Paul Marat (1743-93), key figure of the French Revolution) + H (=husband) + ON (=taking place, not cancelled); the reference is to the Battle of Marathon (490 BC)
Exhibitionist regrets surgery after lift (6)
I haven't cracked this one yet — but Fifteensquared have:
RUES (=regrets) + OP (=surgery, i.e. operation); “after lift” indicates vertical reversal
Anger on stage in a cast (10)
See 12 Across
Terrible blow where driest winds circling it (8)
I haven't cracked this one yet — but Fifteensquared have:
SA (=it, i.e. sex appeal) in *(DRIEST); “winds”, twists, is anagram indicator
Cut down knight in cold Danish city (8)
I haven't cracked this one yet — but Fifteensquared have:
N (=knight, in chess) in [C (=cold, on tap) + ODENSE (=Danish city)]; to condense e.g. material is to compress it, cut it down
Watch insect here shedding wings (6)
I haven't cracked this one yet — but Fifteensquared have:
TICK (=insect, parasite) + <h> ER <e> (“shedding wings” means first and last letters are dropped); colloquially, a ticker is a timepiece, hence “watch”
Sinister Parisian displaying 3 (6)
I haven't cracked this one yet — but Fifteensquared have:
The French (=Parisian) word for left (=sinister) is gauche; someone who is gauche, awkward, is “displaying inelegance (=entry at 3)”
Bad hat seen in opera (Scala) (6)
Fourth man group hated at first (4)
Type letters or click words in the clue