Shilling went in dispatch (5)
I believe the answer is:
speed
'dispatch' is the definition.
(I've seen this before)
'shilling went' is the wordplay.
'shilling' becomes 's'.
'went' becomes 'peed' (both can mean urinated).
's'+'peed'='SPEED'
'in' is the link.
(Other definitions for speed that I've seen before include "Rate of progress" , "Expedition" , "Pace or tempo" , "Rtae of progress" , "A devilish quick driver?" .)