How shop closes, bailiff's work showing bias (13)

'bias' is the definition.
(thesaurus)

'how shop closes bailiff's work showing' is the wordplay.
I cannot quite see how this works, but
'work' could be 'prep' (prep is a kind of work) and 'prep' is found in the answer.
'showing' could be 'on' (I've seen this in other clues) and 'on' is present in the answer.
This may be the basis of clue (or it may be nonsense).