In Dublin see diesel oil producer? (7)
I believe the answer is:
Here is my best explanation:
'oil producer?' is the definition.
'in dublin see diesel' is the subsidiary indication.
'in' indicates a hidden word.
'linseed' can be found hidden inside 'dublin see diesel'.
(Other definitions for linseed that I've seen before include "Product of the flax plant", "Source of plant oil", "Oil-producing plant", "Part of flax used as oil", "Oil produced from flax", "Flax plant product providing oil", "Oil applied to cricket bats", "Enisled (anag.)", "Type of oil" and "Flax product, a source of oil".)