One fighting without aide where work's rough (5,5)
I believe the answer is:
scrap paper
'where work's rough' is the definition.
(paper used for doing rough or draft work)
'one fighting without aide' is the wordplay.
'one fighting' becomes 'scrapper'.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'aide' becomes 'pa' (abbreviation for personal assistant).
'scrapper' placed around 'pa' is 'SCRAP PAPER'.
(Other definitions for scrap paper that I've seen before include "What shamefaced News International decided to do" , "Make jottings on this!" , "somewhere to make notes" .)