Across
Ordinary seaman's two sets of cards (8)
Lighter to bump into (5)
Extent of some software amazing (4)
Welcome s-success, to be admitted here (4,2,4)
Runs after luggage round hotel (6)
I haven't cracked this one yet — but Fifteensquared have:
H in CASES
Marines trained for a year in academy (8)
Serious tennis played by European (7)
Gangster catcalls heard in capital (7)
Competition one may have in the bag (4,4)
Holiday emergency! (6)
Such a gripping tale we hear (10)
Old British settler needed for 20? (4)
Rear small bird (5)
150 of the Romans stand for disinfectant (8)
I haven't cracked this one yet — but Fifteensquared have:
150 is CL in Roman numerals, and Cl is the chemical symbol of, or stands for, Chlorine
Down
Patience when abused may succeed in circling the world (4,4)
Bird that sounds piercing (4)
Ways to secure love that inspires pity (6)
Look up to speaker's lazy eyes (7)
A British girl put on pounds: unusual? (8)
Don't purify murky depth (10)
Before St David's Day the Guardian declares a republic (6)
I haven't cracked this one yet — but Fifteensquared have:
WE (the Guardian) + 1 MAR (St David’s Day)
Petty criminal who tells on his accomplices? (5,5)
Only for men: old woman has time still (8)
Call about oven for cooking (8)
I haven't cracked this one yet — but Fifteensquared have:
OAST (oven) in RIN (call)
Dog we held up in entrance (7)
I haven't cracked this one yet — but Fifteensquared have:
Reverse of WE in BITCH
Stop thief! (6)
I haven't cracked this one yet — but Fifteensquared have:
Arresting a thief would stop him, so it’s a (rather weak) cryptic definition. A pity that “thief” appears in the clue so soon after 13d, where it’s part of the answer
Mule is chewing cereal (6)
Panel put into a box (4)
Type letters or click words in the clue