Voter, say, unexpectedly to be a Remainer? (4,4)

I believe the answer is:

stay over

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'be a remainer?' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'voter say unexpectedly' is the wordplay.
'unexpectedly' indicates an anagram.
'voter'+'say'='votersay'
'votersay' with letters rearranged gives 'STAY OVER'.

'to' acts as a link.

Can you help me to learn more?

(Another definition for stay over that I've seen is " not to leave till morning?".)

I've seen this clue in The Times.

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