Bentley originally in workshop that is put out for collection (7)
I believe the answer is:
garbage
'that is put out for collection' is the definition.
(garbage is put out for collection)
'bentley originally in workshop' is the wordplay.
'originally' says to take the initial letters.
'in' means one lot of letters goes inside another.
'workshop' becomes 'garage' (I've seen this before).
The first letter of 'bentley' is 'b'.
'b' going inside 'garage' is 'GARBAGE'.
(Other definitions for garbage that I've seen before include "Waste, refuse" , "Refuse - a beggar (anag)" , "Litter" , "Rubbish - invalid computer data" , "Nonsense!" .)