Across
Don't attach much importance to power — give up (4,4)
I haven't cracked this one yet — but Fifteensquared have:
for definition e.g. 'plays down the seriousness of the matter' P (power) + LAY DOWN=set aside="give up"
Troublesome place with an effigy? (6)
24d
I need source of metal, Al? Wrong! (4,4)
Expert awfully nice about financial gain? The opposite (10)
I haven't cracked this one yet — but Fifteensquared have:
anagram/"awfully" of (nice)*, inside PROFIT="financial gain" "The opposite" to indicate PROFIT about (nice)* rather than the other way around
Backward boy, not about to become a chemist (6)
I haven't cracked this one yet — but Fifteensquared have:
the chemist is John Dalton [wiki] LAD="boy" reversed/"Backward"; plus NOT reversed/"about"
Most primitive aristocrat that is a good man? (8)
Stone tool in hotel ground (7)
An eleven dismissed, not half worried (7)
College gym by end of term in financial difficulties? (8)
I haven't cracked this one yet — but Fifteensquared have:
there is a Pembroke College in Oxford and a Pembroke College in Cambridge PE (physical education, "gym" class) + end of [ter]-M + BROKE="in financial difficulties"
Explanatory figure lacking a couple of letters together (6)
Being put out, goad union's dinosaurs (10)
2d
Well off, hiding nothing and gawping with awe (4-4)
Think much of Paul? (6)
School group getting a toy package (5,3)
Down
Strangeness seen in a time where deceit is hidden (8)
I haven't cracked this one yet — but Fifteensquared have:
AN AGE="a time", around LIE="deceit"
See 24 across
Clever move possible to get voucher? (6)
Like a deficient cellist maybe, carrying on regardless (7)
I haven't cracked this one yet — but Fifteensquared have:
a cellist uses a bow, so an un-bow-ed cellist might be "deficient"
Versatile newspaper's feature — a relay race? (5,3)
I haven't cracked this one yet — but Fifteensquared have:
a split run of a newspaper has different adverts/articles switched for one another a relay race could be described as a run split into different legs
Making fun of it, as they would be! (10)
Stops Shakespeare's Peter being heard? (6)
I haven't cracked this one yet — but Fifteensquared have:
definition: a quint is a stop on a pipe organ (the musical instrument) sounds ("heard") like 'Quince', and Peter Quince is a character from Shakespeare's A Midsummer Night's Dream
Hospital executive is such a gossip (10)
I haven't cracked this one yet — but Fifteensquared have:
the phrase "Hospi- tal e -xecutive" contains the letters of ' tale ', so it is a ' tale bearer'
Excessively keen to start with, maiden maybe grabbed the reins (4,4)
Woman very old to get married? It's not admitted (8)
Rebels in 'shocking units' led by soldiers (7)
Little bird — one finally given tag (6)
I haven't cracked this one yet — but Fifteensquared have:
final letter of [on]-E, plus AGLET=an ornamental "tag"
Rubbish ex-PM, creating upset (6)
See 10
Type letters or click words in the clue