"Ben-Hur" author (7)
I believe the answer is:
'ben-hur author' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wallace that I've seen before include "Scottish patriot" , "Scottish insurgent" , "Scottish champion" , "With twenty one across, Oscar-winning cartoon pair" , "Edgar ---, crime writer; an art Collection" .)