Across
Moralist turning up in front of train wreck (7)
Singer’s entertaining dad dancing in Somerset village (7)
Start of silly season for Rishi? (4)
Wrecked boat at sea captured by revolutionary French artist (9)
I haven't cracked this one yet — but Fifteensquared have:
BOAT in reverse of (Edgar) DEGAS
Might some garden warblers return? (5)
No.7 in club team (8)
Supplies side-splitting joke (4)
I haven't cracked this one yet — but Fifteensquared have:
EQUIPS (supplies) with its sides having left or “split”
Fellows invested in Spanish couple’s tips (5)
I haven't cracked this one yet — but Fifteensquared have:
F F In DOS (Spanish for 2)
One Republican in US showing a bit of flex (4)
I haven't cracked this one yet — but Fifteensquared have:
1 R in WE (“us” in dialect or careless speech)
Mike goes inside to make a meal for PM (5,3)
I haven't cracked this one yet — but Fifteensquared have:
M[ike] in CREATE A – a cream tea is a meal for the afternoon
Spooner’s subdued fish (5)
I haven't cracked this one yet — but Fifteensquared have:
Spoonerism of “low-key”
Four contrary aliens welcoming a conversation (4-1-4)
I haven't cracked this one yet — but Fifteensquared have:
A in four reversed ETs
OXO rejected fine (4)
I haven't cracked this one yet — but Fifteensquared have:
OXO can be split as OX O, or YAK O, which is then reversed
What Jack Sprat’s wife did on counter holding fine cloth (7)
I haven't cracked this one yet — but Fifteensquared have:
F[ine] in reverse of ATE FAT (“Jack Sprat would eat no fat, his wife would eat no lean…”)
Staggering tax rise for comic character (7)
Down
Department of Justice usually recruits awful leaders (4)
I haven't cracked this one yet — but Fifteensquared have:
First letters of Justice Usually Recruits Awful. Jura is one of the départements of France, named after the Jura mountain range
Discharged current of gas (8)
Masons arranged for someone to do the heavy lifting (6)
American Dad! winning animated Oscar generates media events (5,3)
I haven't cracked this one yet — but Fifteensquared have:
HOT (excited, animated) O[scar] in POPS (mostly American name for a father)
Proverbs in modern times? (6)
I haven't cracked this one yet — but Fifteensquared have:
Modeen times could be A.D. (Anno Domini) AGES
20d
He crashed out before the end of race – that’s bad luck! (4,6)
Maybe attaché provides a clue for B.O.? (9)
Group accepting the ending of Parklife is more offensive (5)
I haven't cracked this one yet — but Fifteensquared have:
[parklif]E in BLUR
The German boy exhausted in race (5)
I haven't cracked this one yet — but Fifteensquared have:
DER (German “the”) + B[o]Y
Test card broadcast from Mars? (8)
Rules written up claiming pole dancing is PC in Australia (8)
I haven't cracked this one yet — but Fifteensquared have:
POLE* in reverse of R[ule] LAW. Chambers says this is old Australian slang for a policeman
Soldier provided that answer for political movement (6)
I haven't cracked this one yet — but Fifteensquared have:
ANT (soldier) + IF (provided that) + A[nswer]
See 6
Jack embracing Zulu king (4)
I haven't cracked this one yet — but Fifteensquared have:
Z in TAR (sailor), Chambers describes this unusual spelling of Tsar/Czar as rare; as TSAR would have fitted just as well, this answer tipped me off to the fact that the puzzle is a pangram (all the letters of the alphabet appear in the answers)
Greedy singer turns up (4)
Type letters or click words in the clue