Across
Ely desperately after pen to house college transport (7)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘to house’) of C (‘college’) in BIC (‘pen’) plus YLE, an anagram (‘desperately’) of ‘Ely’.
Scotsman broken by onset of injury and hard suffering (7)
I haven't cracked this one yet — but Fifteensquared have:
A charade of ANGUIS, an envelope (‘broken by’) of I (‘onset of I njury’) in ANGUS (‘Scotsman’ – a welcome change from Ian); plus H (‘hard’).
Musical piece produced by new department’s head in jumper (5)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘in’) of N (‘new’) plus D (‘ D epartment’s jead’) in ROO (kanga, ‘jumper’).
Burn wayward lazy daughter? Wild! (9)
I haven't cracked this one yet — but Fifteensquared have:
A charade of UNBR, an anagram (‘waywared’) of ‘burn’; plus IDLE (‘lazy’) plus D (‘daughter’).
Sanctimonious little girl in car plant (10)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘in’) of PI (‘sanctimonious’) plus DI (‘little girl’ – with ‘little’ indicating an abbreviation of Diana) in ASTRA (‘car’ – any of various current and previous), which leaves an S hanging – an oversight somewhere?.
See 24 Down
Winner shouts out ‘There’s no merit in it!’ (12)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (‘out’) of ‘winner shouts’.
Admonition, it seems, about breaking into song (12)
Mechanical routine giving balls energy (4)
I haven't cracked this one yet — but Fifteensquared have:
A charade of ROT (‘balls’) plus E (‘energy’).
Maybe London’s joint originator of written work (10)
I haven't cracked this one yet — but Fifteensquared have:
A charade of AUTHOR’S (‘maybe London’s’ – a reference to Jack London) plus HIP (‘joint’). The definition suggests to me AUTHOR rather than AUTHORSHIP.
Dash, it’s rough being an ambitious type! (9)
Mark 2? (5)
I haven't cracked this one yet — but Fifteensquared have:
Samuel Clemens wrote under the pseudonym Mark Twain, chosen for the cry indicating a river’s depth of two fathoms, safe for a Missisippi steamboat. Hardly a cryptic clue.
Backing positive, steadfast youth leaders to undertake major journey (7)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (‘backing’) of YES (‘positive’) plus SY (‘ S teadfast Y outh leaders’) plus DO (‘undertake’).
Level of society needing pluck to restrain a totalitarian leader (7)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘to restrain’) of ‘a’ plus T (‘ T otalitarian leader’) in STRUM (‘pluck’ – an obvious choice for the surface, but not a good synonym for a string player).
Down
Lawyers’ bill for drink (6)
Tester of prison work finally happy (6)
I haven't cracked this one yet — but Fifteensquared have:
A charade of CAN (‘prison’) plus OP ( opus , ‘work’) plus Y (‘finally happ Y ‘); one of the meanings of a ‘tester’ is a canopy over a bed.
Decoration designed for X? (10)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (‘designed’) of ‘decoration’, with an indication by example, hence the question mark.
Cast use Queen Ursula’s debut play (5)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (‘cast’) of ‘use’ plus Q (‘Queen’) plus U (‘ U rsula’s debut’), for the theatre piece by Peter Schaffer.
True! Rambo’s swimming trunks to be seen here (9)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (‘swimming’) of ‘true Rambo’, with ‘trunks’ referring to trees.
One’s fitted in gun carriage (4)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘fitted in’) of I (‘one’) in GAT (‘gun’).
Denials about cigar butt being Cuban? (8)
I haven't cracked this one yet — but Fifteensquared have:
A charade of ISLANDE, an anagram (‘about’) of ‘denials’; plus R (‘ciga R butt’), again with an indication by example.
No puritan, involving fellow in theft (8)
One who works over the shop? (4-6)
Book set in US city or miserable, dark state (9)
I haven't cracked this one yet — but Fifteensquared have:
An envelope (‘set in’) of B (‘book’) in OSCURITY, an anagram (‘miserable’) of ‘US city or’.
Singular Côte d’Ivoire architectural style – O! is lost; quite a blow (8)
I haven't cracked this one yet — but Fifteensquared have:
A charade of S (‘singular’) plus CI (‘Côte d’Ivoire’, IVR) plus ROC[o]CO (‘architectural style’) minus an O (‘O! is lost’), for a strong hot Mediterranean wind, also written sirocco.
Drink associated with railway in recent times (8)
See 24
Brummie’s refusal to do a turn as the title character (6)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (‘to do a turn’) of MY (‘Brummie’s’) plus NOPE (‘refusal’).
Basic construction by American-Africans (5)
19d
Joins the performance of Tosca (teen night production) (4,2,2,3,3)
Type letters or click words in the clue