Marie ____'s work in wax included a self-portrait still shown at the London museum she founded (7)
I believe the answer is:
tussaud
(Other definitions for tussaud that I've seen before include "Madame ..., wax modeller with London exhibition" , "Marie -, French wax-modeller" , "Waxworks impresario" , "Madame -, French wax modeller" .)