On the wrong side where banks are concerned (2,3,3)
I believe the answer is:
in the red
'concerned' is the definition.
Both the answer and definition are adjectives.
Perhaps there's an association between them I don't understand?
'on the wrong side where banks' is the wordplay.
I cannot quite see how this works, but
'on' could be 're' (regarding) and 're' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'are' acts as a link.
Can you help me to learn more?
(Other definitions for in the red that I've seen before include "Owing money, bank account overdrawn" , "needing cash injection" , "OD - with 23 & part of 13a" , "Santa appears thus" , "Flashing lamp" .)