The capital of South Australia (8)
I believe the answer is:
adelaide
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the capital of south australia</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for adelaide that I've seen before include "Australian city named for William IV's queen" , "19th century queen" , "South Australia's capital" , "Antipodean city" , "Lead aide out to Australia" .)