Old requirement to include special documentation meeting little opposition (3-5)

I believe the answer is:

one-sided

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'old requirement to include special documentation meeting little opposition' is the definition.
I can't judge whether this definition defines the answer.

'old requirement to include special documentation' is the wordplay.
'old' becomes 'o' (abbreviation).
'requirement' becomes 'need' (synonyms).
'to include' is an insertion indicator.
'special' becomes 'S' (common abbreviation as in Special Air Service).
'documentation' becomes 'ID' (identification documents).
's'+'id'='sid'
'need' placed around 'sid' is 'nesided'.
'o'+'nesided'='ONE-SIDED'

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(Other definitions for one-sided that I've seen before include "Unfairly biased" , "Partial" , "Unbalanced" , "Unfair or uneven" , "Unfair or partisan - single dimension?" .)

I've seen this clue in The Independent.

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