Not very musical group soon releasing covers (4,3)

I believe the answer is:

none too

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'not' is the definition.
I know nothing about this answer so I can't judge whether this works.

'musical group soon releasing covers' is the wordplay.
'musical group' becomes 'nonet' (group of nine musicians).
'soon releasing covers' becomes 'oo' (I can't justify this - if you can you should believe this answer much more).
'nonet'+'oo'='NONE TOO'

'very' acts as a link.

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I've seen this clue in The Times.

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