The gardener's boy? (3)

I believe the answer is:

den

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'boy?' is the definition.

'the gardener's' is the wordplay.
'DEN' is hidden in amongst the letters.
But, I am uncertain how this is indicated.

Can you help me to learn more?

(Other definitions for den that I've seen before include "Animal's home or gent's study" , "Animal shelter" , "Miserable place" , "Home of the beast" , "Habitation of wild animals (3)" .)

I've seen this clue in the Evening Standard.

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