Battle nerve is to bandage cut in retreat (9)
I believe the answer is:
gallipoli
'battle' is the definition.
(Battle of Gallipoli, WW1 campaign)
'nerve is to bandage cut in retreat' is the wordplay.
I cannot quite understand how this works, but
'nerve' could be 'gall' (both can mean rudeness or impertinence) and 'gall' is found within the answer.
This explanation may well be incorrect...
(Other definitions for gallipoli that I've seen before include "military invasion" , "military campaign" , "Long ago landing" , "old war-zone" , "Turkish scene of WW1 landing" .)