Composed personally, when alone (2,7)

I believe the answer is:

by oneself

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'alone' is the definition.
(on one's own)

'composed personally' is the wordplay.
'composed' becomes 'by' (I can't justify this - if you can you should give a lot more credence to this answer).
'personally' becomes 'oneself' (I've seen this before).
'by'+'oneself'='BY ONESELF'

'when' acts as a link.

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I've seen this clue in the Evening Standard.

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