Collectors' vehicle (8)
I believe the answer is:
'collectors' vehicle' is the definition.
'dustcart' can be an answer for 'vehicle' (dustcart is a kind of vehicle). I'm unsure of the 'collectors'' bit.
'collectors' vehicle' is the wordplay.
'collectors'' becomes 'dust' (I can't justify this - if you can you should believe this answer much more).
'vehicle' becomes 'cart' (cart is a kind of vehicle).
Can you help me to learn more?
(Other definitions for dustcart that I've seen before include "Vehicle for collecting rubbish" , "Rubbish-collecting vehicle" , "Refuse vehicle" , "Council vehicle" , "Refuse collector" .)