Work of art needing expedition on credit reportedly? (8)
I believe the answer is:
triptych
'work of art' is the definition.
(I've seen this before)
'expedition on credit reportedly?' is the wordplay.
'expedition' becomes 'trip' (I've seen this in another clue).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'credit' becomes 'tick' (on tick can mean purchased on credit).
'reportedly?' indicates a 'sounds like' (homophone) clue (I've seen 'reportedly' mean this).
'tick' sounds like 'tych'.
'trip'+'tych'='TRIPTYCH'
'needing' acts as a link.
(Other definitions for triptych that I've seen before include "Three-panelled picture" , "Hit crypt (anag) - painting" , "Picture with three panels" , "Three-part picture" , "Painting on three hinged panels" .)