He has a fruitful business in romantic Osterley (6)
I believe the answer is:
'he has a fruitful business' is the definition.
The definition suggests a singular noun which matches the answer.
'in romantic osterley' is the wordplay.
'in' says the answer is hidden in the clue.
'COSTER' is hidden within 'romantic osterley'.
Can you help me to learn more?
(Other definitions for coster that I've seen before include "Street trader" , "Seller of goods from a barrow" , "who must price his goods" , "Fruit and veg seller" , "Seller of wares from a barrow" .)