Where, formerly, putting the finish before the start led to anger! (5)
I believe the answer is:
zaire
'where formerly putting the finish before' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
'start led to anger' is the wordplay.
'start led' becomes 'za' (I can't justify this - if you can you should give a lot more credence to this answer).
'to anger' becomes 'ire' (ire is intense rage).
'za'+'ire'='ZAIRE'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for zaire that I've seen before include "somewhere abroad, recalled?" , "Democratic Republic of Congo's former name" , "Former name of DRC" , "Until 1997 the name of the Democratic Republic of the Congo" , "renamed African area" .)