Immaculate location? Not so! (8)
I believe the answer is:
spotless
'immaculate' is the definition.
(I know that immaculate can be written as spotless)
'location? not so' is the wordplay.
'location?' becomes 'spot' (spot is a kind of location).
'not so' becomes 'less' (eg 'not so big' means 'less big').
'spot'+'less'='SPOTLESS'
(Other definitions for spotless that I've seen before include "Extremely clean" , "free from sin" , "Irreproachably clean" , "Without a mark, completely clean" , "What unsuccessful twitchers do" .)