Sudden impulse to see Italian island church (7)
I believe the answer is:
caprice
'sudden impulse' is the definition.
(I've seen this before)
'italian island church' is the wordplay.
'italian island' becomes 'capri' (Capri is an Italian island).
'church' becomes 'CE' (abbreviation for Church of England).
'capri'+'ce'='CAPRICE'
'to see' is the link.
(Other definitions for caprice that I've seen before include "Sudden whim" , "'Impulse, whim (7)'" , "A whim, or piece of music in lively fanciful style" , "Whimsy" , "Sudden change of mind" .)