Dispatched in Isleworth (4)
I believe the answer is:
slew
'dispatched' is the definition.
(I've seen this in another clue)
'in isleworth' is the wordplay.
'in' says the answer is hidden in the clue.
'SLEW' can be found hidden inside 'isleworth'.
(Other definitions for slew that I've seen before include "Uncontrollable turn/slide" , "skid" , "making sharp turn" , "Greatly amused" , "Large number -- killed" .)