Something of a catch, daughter ended single (5,4)
I believe the answer is:
dover sole
'something of a catch' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'daughter ended single' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'ended' becomes 'over' (synonyms).
'single' becomes 'sole' (synonyms).
'd'+'over'+'sole'='DOVER SOLE'
Can you help me to learn more?
(Other definitions for dover sole that I've seen before include "Kentish flat fish" , "Catch" .)