Soldiers involved in attack, lost one — it’s hard cheese (8)
I believe the answer is:
parmesan
'hard cheese' is the definition.
(I've seen this before)
'soldiers involved in attack lost one it's' is the wordplay.
I cannot really understand how this works, but
'one' could be 'an' ('a' and 'an' can mean 'one') and 'an' is present in the answer.
'it's' could be 'es' ('e' can mean 'electronic' which is similar to 'IT') and 'es' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for parmesan that I've seen before include "Italian 8 across" , "that's grated" , "that grates" , "Hard dry cheese, often grated" , "Italian cheese for spearman" .)