Vehicle collection (7)
I believe the answer is:
omnibus
I believe this clue is a double definition.
'vehicle' is the first definition.
(I've seen this before)
'collection' is the second definition.
(I have seen 'Collection of works' mean 'omnibus' so perhaps 'collection' could also mean 'omnibus')
(Other definitions for omnibus that I've seen before include "Large vehicle - collected edition" , "Charabanc" , "Large passenger vehicle - collection of printed works in one volume" , "Extended programme" , "Compendium volume" .)