Bathroom fixture I'd installed in punt (5)
I believe the answer is:
bidet
'bathroom fixture' is the definition.
(I've seen this in another clue)
'i'd installed in punt' is the wordplay.
'installed in' is an insertion indicator.
'punt' becomes 'bet' (punt can mean a bet).
'id' inserted into 'bet' is 'BIDET'.
(Other definitions for bidet that I've seen before include "Bathroom facility" , "Bathroom fixture" , "Washing facility" , "Bathroom item" , "Cleaning vessel for privates" .)