Leaving notes on split (9)

I believe the answer is:

departing

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'leaving' is the definition.
('depart' can be a synonym of 'leave')

'notes on split' is the wordplay.
'notes' becomes 'de' (two musical notes).
'on split' becomes 'parting' (I can't explain this - if you can you should believe this answer much more).
'de'+'parting'='DEPARTING'

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I've seen this clue in The Daily Express.

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