Irish love business paper illustrating hard work (5)
I believe the answer is:
graft
'hard work' is the definition.
(graft can mean working hard)
'irish love business paper' is the wordplay.
'irish love' becomes 'gra' (I've seen this in another clue).
'business paper' becomes 'ft' (Financial Times newspaper).
'gra'+'ft'='GRAFT'
'illustrating' is the link.
(Other definitions for graft that I've seen before include "Shoot; hard work" , "Hard work - illicit gain" , "Transfer of tissue - hard work!" , "Hard work - corrupt profit" , "Slip" .)