… determined to provide late fix (4,3)
I believe the answer is:
dead set
'determined to' is the definition.
(synonyms)
'late fix' is the wordplay.
'late' becomes 'dead' (similar in meaning).
'fix' becomes 'set' (synonyms).
'dead'+'set'='DEAD-SET'
'provide' acts as a link.
(Other definitions for dead set that I've seen before include "Absolutely - sedated (anag)" , "Fixed in one's purpose" , "A determined attack - from moribund group?" , "Determined (upon)" , "Complete standstill; sedated (anag.)" .)