Group fans get so foul about Mary’s helper? (8,2,5)

I believe the answer is:

spoonful of sugar

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'mary's helper?' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'group fans get so foul about' is the wordplay.
'get' says to put letters next to each other.
'about' indicates an anagram.
'group'+'fans'+'so'+'foul'='groupfanssofoul'
'groupfanssofoul' with letters rearranged gives 'SPOONFUL OF SUGAR'.

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I've seen this clue in the Sydney Morning Herald.

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