Banned brown sauce, used in fish, to make extreme point (5,4)
I believe the answer is:
'extreme point' is the definition.
(southernmost point on Earth)
'banned brown sauce used in fish' is the wordplay.
'banned' becomes 'out'.
'brown sauce' becomes 'HP' (HP is a condiment brand).
'used in' is an insertion indicator.
'fish' becomes 'sole' (sole is a kind of fish).
'outhp' put inside 'sole' is 'SOUTH POLE'.
'to make' acts as a link.
(Other definitions for south pole that I've seen before include "Goal of explorers" , "to which Scott came" , "Amundsen got there first, before Scott" , "gets very cold!" , "Antarctic" .)