One supervising Sellers in Goon realm, far gone (5,7)

I believe the answer is:

floor manager

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'one supervising sellers' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'goon realm far gone' is the wordplay.
'goon realm far' anagrams to 'FLOOR MANAGER'.
However, I'm not sure how this is indicated.

'in' acts as a link.

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I've seen this clue in The Times.

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