Prefect’s companion very keen to seize the day (6,4)

I believe the answer is:

arthur dent

'prefect's companion' is the definition.
(Hitchhiker's Guide to the Galaxy character)

'very keen to seize the day' is the wordplay.
'very keen' becomes 'ardent' (I've seen this before).
'to seize' is an insertion indicator.
'the day' becomes 'thur' (abbreviation for Thursday).
'ardent' going around 'thur' is 'ARTHUR DENT'.

I've seen this clue in The Times.

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