Playing on cellos or working on the base? (8)

I believe the answer is:

colonels

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'or working on the base?' is the definition.
I can't tell whether this definition defines the answer.

'playing on cellos' is the wordplay.
'playing' is an anagram indicator.
'on'+'cellos'='oncellos'
'oncellos' with letters rearranged gives 'COLONELS'.

Can you help me to learn more?

(Other definitions for colonels that I've seen before include "Senior military officers" , "Military personnel" .)

I've seen this clue in The Irish Times.

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