In the open air in Coles? Far out! (8)
I believe the answer is:
'in the open air' is the definition.
(I've seen this before)
'coles? far out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'colesfar' with letters rearranged gives 'ALFRESCO'.
'in' acts as a link.
(Other definitions for alfresco that I've seen before include "exposed to the fresh air", "Outdoors, meal perhaps", "In the open air", "Meal eaten in the outdoors", "where it's cool".)