In the open air in Coles? Far out! (8)
I believe the answer is:
alfresco
'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).
'coles'+'far'='colesfar'
'colesfar' with letters rearranged gives 'ALFRESCO'.
'in' acts as a link.
(Other definitions for alfresco that I've seen before include "where it's cool" , "In the open air" , "Outside" , "Out of doors" , "Located outdoors" .)