Unbroken view, or restricted by hat? (8)
I believe the answer is:
panorama
'unbroken view' is the definition.
(I've seen this before)
'or restricted by hat?' is the wordplay.
'restricted by' is an insertion indicator (I've seen this in other clues).
'hat?' becomes 'panama' (panama is a kind of hat).
'or' placed within 'panama' is 'PANORAMA'.
(Other definitions for panorama that I've seen before include "Wide-angle shot" , "Wide view - TV programme" , "long-running programme" , "Wide unbroken view" , "Comprehensive survey" .)