Makes amends with garland, certainly, whenever convenient (2,4,7)

I believe the answer is:

at ones leisure

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'whenever convenient' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'makes amends with garland certainly' is the wordplay.
'makes amends' becomes 'atones' (I've seen this before).
'with' says to put letters next to each other.
'garland' becomes 'lei' (synonyms).
'certainly' becomes 'sure' (synonyms).
'atones'+'lei'+'sure'='AT ONES LEISURE'

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(Another definition for at ones leisure that I've seen is " Free from occupation".)

I've seen this clue in The Times.

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