Like the Duke of Edinburgh, soon had deer roundly shot (7-4-3)

I believe the answer is:

hundred-year-old

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'like the duke of edinburgh soon' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'had deer roundly shot' is the wordplay.
'shot' indicates an anagram.
'had'+'deer'+'roundly'='haddeerroundly'
'haddeerroundly' with letters rearranged gives 'HUNDRED-YEAR-OLD'.

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I've seen this clue in The Guardian.

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