Years with Labour deliver peanuts, unfortunately (5,9)

I believe the answer is:

penal servitude

I'm a little stuck... Click here to teach me more about this clue!

'years with labour' is the definition.
I can't judge whether this definition defines the answer.

'deliver peanuts unfortunately' is the wordplay.
'unfortunately' is an anagram indicator (a bad or unfortunate spelling).
'deliver'+'peanuts'='deliverpeanuts'
'deliverpeanuts' with letters rearranged gives 'PENAL SERVITUDE'.

Can you help me to learn more?

(Another definition for penal servitude that I've seen is " Imprisonment with hard labour".)

I've seen this clue in The Independent.

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