Anonymous, so idler became a war hero (7,7)

I believe the answer is:

unknown soldier

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'a war hero' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?

'anonymous so idler became' is the wordplay.
'anonymous' becomes 'unknown' (similar in meaning).
'became' indicates anagramming the letters (I've seen 'becoming' mean this).
'idler' is an anagram of 'ldier'.
'unknown'+'so'+'ldier'='UNKNOWN SOLDIER'

Can you help me to learn more?

I've seen this clue in The Daily Express.

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