Wizard banner returned and brought in (7)
I believe the answer is:
gandalf
'wizard' is the definition.
(I've seen this before)
'banner returned and brought in' is the wordplay.
'banner' becomes 'flag' (I've seen this before).
'returned' shows that the letters should be reversed in order.
'brought in' is an insertion indicator.
'flag' back-to-front is 'galf'.
'galf' going around 'and' is 'GANDALF'.
(Other definitions for gandalf that I've seen before include "Tolkien character" , "Tolkien's wizard" .)