All right to be got up in the style of Australian native (5)
I believe the answer is:
'australian native' is the definition.
(I've seen this before)
'all right to be got up in the style of' is the wordplay.
'all right' becomes 'ok' (synonyms).
'to be got up' shows that the letters should be reversed in order.
'in the style of' becomes 'ala' (I've seen this before).
'ok' written backwards gives 'ko'.
(Other definitions for koala that I've seen before include "Arboreal Australian native" , "One's usually up a tree" , "Marsupial "bear"" , "Eater of eucalyptus" , "Australian tree-climbing marsupial with grey fur and big ears" .)