Utter failure if return made in the manner of small company (6)
I believe the answer is:
fiasco
'utter failure' is the definition.
(I've seen this in another clue)
'if return made in the manner of small company' is the wordplay.
'return' says the letters should be written in reverse.
'made in the manner of' becomes 'as' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'small company' becomes 'co' (abbreviation; 'small' asks for an abbreviation).
'if' backwards is 'fi'.
'fi'+'as'+'co'='FIASCO'
Can you help me to learn more?
(Other definitions for fiasco that I've seen before include "Ignominious failure" , "Sudden and complete collapse" , "Ignominious result" , "Ridiculous and total failure" , "An absolute mess, what a farce" .)