Across
Boycott gets 50 and left balls in bag (7)
I haven't cracked this one yet — but Fifteensquared have:
BAN (boycott) round L (fifty) + L (left) + OO (balls)
They say sitcom family cuppa has majestic quality (7)
Knight undressed noblewoman (4)
Lied about Conservative promises being tasteful (9)
New? My mistake sending back old club (5)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (sending back) of N (new) + OOPS (my mistake); years ago, this old golf club used to feature quite regularly in crosswords – and it was old-fashioned then!
Fair river in China (8)
In Sweden, I was knocking back drink (4)
Frightened son leaving to be looked after (5)
Salmon provided by shop in Kensington (4)
Persuades wife to pay attention to Dennis (8)
Asian state content to leave ludicrous targets (5)
I haven't cracked this one yet — but Fifteensquared have:
GOA (Asian state) + L[udicrou]S
USA proven to distress star having a meltdown (9)
Mountain tops in France, usually just ice (4)
Repeats one's rights during revolting arrest (7)
I haven't cracked this one yet — but Fifteensquared have:
A (one) + RR (rights) in a reversal (revolting) of STOP (arrest)
No longer held fun rave with zero dancing (7)
Down
After excluding two unknowns, group of stars party (4)
150 may riot over European money for weapon (8)
Successful in Australia, Kelly's record is revoked (6)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (revoked) of NED (Kelly) + LOG (record) – I’m not sure why ‘in Australia’, apart from the reference to Ned Kelly
Before Conservative Party's finished, Johnson finally quit and gave up (8)
I haven't cracked this one yet — but Fifteensquared have:
CON (Conservative) + E[n]DED minus n (last letter of Johnson) – I’m sure it’s staring me in the face but I can’t quite see how to fit in the second C or ‘before’ – it’s a great surface, anyway
Various nuts lacking individual taste (6)
Overseas characters stuff up (4)
White meat course partially cooked (9)
Oscar winner shockingly hits man's face (5)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (shockingly) of HITS M[an’s] – the clue refers to an incident in the Oscars ceremony where the winner, Will Smith, appeared to hit the presenter, see here
Big actor briefly dropping hot containers (5)
I haven't cracked this one yet — but Fifteensquared have:
T [om] [h]ANKS (Big actor, briefly) minus h (hot) – Tom Hanks was the star of the film ‘Big’ – thanks Blaise @11
Big shot getting bowled out in haste (8)
Mountain climbing? Time for mega-stand (8)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (climbing, in a down clue) of ALP (mountain) + T (time) + FOR + M (mega)
Britain had one politician detained by Ireland (6)
Relative managed to break into key US city (6)
I haven't cracked this one yet — but Fifteensquared have:
RAN (managed) in G (key) + NY (US city)
Playwright was upset about ending of Macbeth (4)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (upset) of WAS round macbetH
European agreement on snoring being music (4)
Type letters or click words in the clue