In Australian Regular Army, two hundred for African capital (5)
I believe the answer is:
accra
'african capital' is the definition.
(capital of Ghana)
'in australian regular army two hundred' is the wordplay.
'in' is an insertion indicator.
'australian regular army' becomes 'ara' (this could be a standard abbreviation which I don't know about).
'two hundred' becomes 'cc' (roman numerals).
'ara' placed around 'cc' is 'ACCRA'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for accra that I've seen before include "West Africa capital" , "Ghanaian capital" , "Capital of Ghana, African fritter" , "Main city of Ghana" , "Ghanaian city" .)