Hornets upset when sat on (7)

I believe the answer is:

thrones

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'when sat on' is the definition.
I can't judge whether this definition defines the answer.

'hornets upset' is the wordplay.
'upset' indicates an anagram.
'hornets' with letters rearranged gives 'THRONES'.

Can you help me to learn more?

(Another definition for thrones that I've seen is " Seats for royalty".)

I've seen this clue in the Evening Standard.

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