The control in that place (7)
I believe the answer is:
therein
'in that place' is the definition.
(I've seen this before)
'the control' is the wordplay.
'control' becomes 'rein' (rein is a kind of control).
'the'+'rein'='THEREIN'
(Other definitions for therein that I've seen before include "in that respect" , "Neither (anag) - into that" , "enclosed by that place?" , "Inside that" .)