Profitable scheme remains limited by County Council? That’s painful (4,3)
I believe the answer is:
cash cow
'profitable scheme' is the definition.
The definition and answer can be both related to thinking as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'remains limited by county council? that's painful' is the wordplay.
'remains' becomes 'ash' (remains of a fire).
'limited by' indicates putting letters inside (limit can mean to contain or border off).
'county council?' becomes 'cc' (this could be a standard abbreviation which I don't know about).
'that's painful' becomes 'ow' (I've seen this in other clues).
'ash' put within 'cc' is 'cashc'.
'cashc'+'ow'='CASH COW'
Can you help me to learn more?
(Other definitions for cash cow that I've seen before include "Business making large profits" , "Money-spinning business" , "Lucrative activity" , "Saw choc (anag.); steady investment" , "E.g. business milked for money" .)