Crossword Genius

Clap artist with pipes performing 'Signed, Sealed, Delivered'? (4,11)

Ross

I believe the answer is:

past participles

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''signed sealed delivered'?' is the definition.
I can't tell whether this definition defines the answer.

'clap artist with pipes performing' is the wordplay.
'with' says to put letters next to each other.
'performing' is an anagram indicator (the letters move around or 'perform').
'clap'+'artist'+'pipes'='clapartistpipes'
'clapartistpipes' with letters rearranged gives 'PAST PARTICIPLES'.

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I've seen this clue in The Independent.
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