Fictional detective in mews I reportedly upset (4,5,6)

I believe the answer is:

lord peter wimsey

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'fictional detective' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'mews i reportedly upset' is the wordplay.
'upset' is an anagram indicator.
'mews'+'i'+'reportedly'='mewsireportedly'
'mewsireportedly' with letters rearranged gives 'LORD PETER WIMSEY'.

'in' is the link.

Can you help me to learn more?

(Another definition for lord peter wimsey that I've seen is " fictional character".)

I've seen this clue in The Telegraph.

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