Girl, to an Aussie (6)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">girl to an aussie</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sheila that I've seen before include "Female name" , "Girl's name (any Oz girl?)" , "Girl's name; Six down (anag.)" , "Woman (Aus. colloq.)" , "Informal Australian girl - could be Irish" .)