A key adviser somewhere in Australia (8)
I believe the answer is:
adelaide
'somewhere in australia' is the definition.
(I've seen this before)
'a key adviser' is the wordplay.
'key' becomes 'del' (Delete on a keyboard).
'adviser' becomes 'aide'.
'a'+'del'+'aide'='ADELAIDE'
(Other definitions for adelaide that I've seen before include "old consort" , "Australian city named for William IV's queen" , "19th century queen" , "Australian capital" , "Antipodean city" .)