If you look at the whole page there are a few instances, like this one, where the occupation has been overwritten with another word. For instance at the top of the page the word 'laundress' has been overwritten with the word 'Wash'.
This is where, after the census page was written up, someone went through it extracting information for statistical purposes, in some cases writing the occupational classification over the original word.
I think what has happened in Walter's case is that originally what was written was simply 'artist' and this has been placed in the occupational classification of 'Sculptors, Painters, Engravers, (Artists)', hence the word 'Sculp' written over 'Artist'
Relevant page from the 1901 classifications here
http://www.rootschat.com/links/01e9t/