Across
Splendid Welsh league accepting representation of founder (9)
I haven't cracked this one yet — but Fifteensquared have:
*(FOUNDER) in [W (=Welsh) + L (=league); “representation of” is anagram indicator
Relative turned about to go for soup (5)
I haven't cracked this one yet — but Fifteensquared have:
BROTH <er> (=relative; “turned (=reversed) about (=re-, regarding) to go (=be dropped)” means letters “er” are dropped)
Face consuming supply of tea every 24 hours (7)
Former Queen in flamboyant clothing experiencing damp weather (7)
Dark period with good hearts suppressed by idiot (5)
I haven't cracked this one yet — but Fifteensquared have:
[G (=good) + H (=hearts, i.e. suit in cards)] in NIT (=idiot)
Try dropping unknown firearm not given to wounding (9)
Such characters in old ode? (3)
I haven't cracked this one yet — but Fifteensquared have:
semi- & lit .; the odd (=not even) characters (=letters) in O <l> D <o> D <e> give the word “odd (=unusual, rare)”, which the letters in an old poem may well be!
Feel pride say after former schoolfellow returned as biographer (7)
Title is backed by publisher finally (3)
I haven't cracked this one yet — but Fifteensquared have:
SI (IS; “backed” indicates reversal) + <publishe> R (“finally” means last letter only)
Number of attendees to drop? Get in without paying (9)
Horseplay when coming round to bed (5)
A lot of wind leads to oppressive rain and bad conditions (7)
I haven't cracked this one yet — but Fifteensquared have:
SQUAL <l> (=wind; “a lot of” means last letter is dropped) + O <ppressive> R <ain> (“leads to” means first letter of each is needed)
Sword carrier without charm not entirely well-set-up (7)
Form line when entering Court of Session (5)
I haven't cracked this one yet — but Fifteensquared have:
[L (=line) + AS (=when, as conjunction)] in CS (=Court of Session); a form is a class in a school
Time in Church House ignoring special sponsorship (9)
I haven't cracked this one yet — but Fifteensquared have:
T (=time) in PAR <s> ONAGE (=church house; “ignoring special (=S)” means letter “s” is dropped)
Down
Mystical scientist sending river into European country marsh (10)
I haven't cracked this one yet — but Fifteensquared have:
R (=river) in [SWEDEN (=European country) + BOG (=marsh)]; the reference is to the Swedish mystic scientist Emanuel Swedenborg (1688-1772)
I note failure to restrain large pet (8)
I haven't cracked this one yet — but Fifteensquared have:
I + N + [LGE (=large) in DUD (=failure, flop)]; as an adjective, pet means favourite, indulged, pampered
Seed a Parisian turned up in vegetable matter (6)
A lot of commotion about dull inspiration (8)
I haven't cracked this one yet — but Fifteensquared have:
FLAT (=dull, uninspired) in [A + FUS <s> (=commotion, ado; “a lot of” means last letter is dropped)]
Ionised gas: contrived a sample to emit energy (6)
I haven't cracked this one yet — but Fifteensquared have:
*(A SAMPL <e>); “to emit energy (=E)” means letter “e” is dropped from anagram, indicated by “contrived”; in physics, plasma is a very hot ionised gas
Strange Buddhist priest heading heavenwards newly born inside (8)
Doctor satisfied about national importance (6)
I haven't cracked this one yet — but Fifteensquared have:
MO (=doctor, i.e. Medical Officer) + [N (=national, as in RNLI) in MET (=satisfied, i.e. condition)]
Question importing English dairy product (4)
Storyteller has buckled horn carried by vagrant cleric (10)
Spooner’s to miss party leading to unpleasant response (8)
I haven't cracked this one yet — but Fifteensquared have:
Spoonerism of “ l ack (=(to) miss) + b ash (=party)”
Cut up about greeting piece of early evidence? (8)
I haven't cracked this one yet — but Fifteensquared have:
[HI (=greeting) + BIT (=piece of)] in EXA (AXE=cut; “up” indicates vertical reversal); logically, Exhibit A will come before Exhibit B, C, D, in a court case
Malaysian dish keeping Pakistani all but enthralled for 24 hours (8)
Bird in quantity of film after holiday cut short (6)
Rough area dry containing phosphorus (6)
I haven't cracked this one yet — but Fifteensquared have:
A (=area) + [P (=phosphorus) in BRUT (=dry, of champagne)]; a rough, short manner is abrupt
Go behind congregation mostly depressed (6)
Item of clothing very much attached to designer logo? (4)
Type letters or click words in the clue