Work Ben undid without being asked (8)
I believe the answer is:
unbidden
'without being asked' is the definition.
(I've seen this before)
'work ben undid' is the wordplay.
'work' indicates anagramming the letters.
'ben'+'undid'='benundid'
'benundid' anagrammed gives 'UNBIDDEN'.
(Other definitions for unbidden that I've seen before include "Spontaneous - not invited" , "Without having been invited" , "Not commanded" , "Without being asked" , "Uninvited, spontaneous" .)