Attended to in hospital again, having left the war zone (9)
I believe the answer is:
retreated
'left the war zone' is the definition.
'retreated' can be an answer for 'left' (I've seen this before). I am not certain of the 'the war zone' bit.
'attended to in hospital again' is the wordplay.
I cannot quite understand how this works, but
'again' could be 're' (prefix meaning 'again') and 're' is present in the answer.
'attended to' could be 'treated' (I've seen this before) and 'treated' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'having' is the link.
Can you help me to learn more?
(Other definitions for retreated that I've seen before include "Left" , "Went back" , "Retired" , "pulled back" , "Withdrew from enemy forces" .)