Hired to provide evidence that ladies are being used (7)
I believe the answer is:
engaged
I believe this clue is a double definition.
'hired' is the first definition.
('engage' can be a synonym of 'hire')
'evidence that ladies are being used' is the second definition.
(engaged can mean a toilet is being used)
'to provide' is the link.
(Other definitions for engaged that I've seen before include "Bethrothed" , "May as well ring off" , "Preoccupied" , "Not free" , "In use" .)