Quietly cheers about seats (7)

I believe the answer is:

perches

'seats' is the definition.
(I know this)

'quietly cheers about' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'about' is an anagram indicator.
'cheers' is an anagram of 'erches'.
'p'+'erches'='PERCHES'

(Another definition for perches that I've seen is " Roosts".)

I've seen this clue in The Mirror.

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