Poor imitation waistcoat in back of ute (8)
I believe the answer is:
travesty
'poor imitation' is the definition.
'waistcoat in back of ute' is the wordplay.
'waistcoat' becomes 'vest' (synonyms).
'in' is an insertion indicator.
'back of ute' becomes 'tray' (I can't justify this - if you can you should give a lot more credence to this answer).
'vest' put into 'tray' is 'TRAVESTY'.
Can you help me to learn more?
(Other definitions for travesty that I've seen before include "False or distorted representation of something" , "Ridiculous version of the genuine article" , "Grotesque representation" , "Farcical imitation" , "Make fun of" .)