Strong-willed woman caused royal din (4,4)
I believe the answer is:
iron lady
'strong-willed woman' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'caused royal din' is the wordplay.
'caused' is an anagram indicator (I've seen 'causing' mean this).
'royal'+'din'='royaldin'
'royaldin' is an anagram of 'IRON LADY'.
Can you help me to learn more?
(Other definitions for iron lady that I've seen before include "at No 10, once?" , "The one who was "not for turning"" .)