Barrel transporting vintage spirit across island (3,4)
I believe the answer is:
oil drum
'barrel' is the definition.
(I know that oil drum is a type of barrel)
'vintage spirit across island' is the wordplay.
'vintage' becomes 'old' (I've seen this in another clue).
'spirit' becomes 'rum' (alcoholic spirit).
'across' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'old'+'rum'='oldrum'
'oldrum' enclosing 'i' is 'OIL-DRUM'.
'transporting' acts as a link.
This may not be correct. It may be part of another bit of the clue.
(Other definitions for oil drum that I've seen before include "Large container" , "Metal barrel for fuel" , "Fuel container" , "Container for crude" .)