Ancient old boy set up wine store (6)
I believe the answer is:
bodega
'wine store' is the definition.
(I've seen this before)
'ancient old boy set up' is the wordplay.
'ancient' becomes 'aged' (ancient can mean very aged).
'old boy' becomes 'OB' (abbreviation for a private school 'old boy').
'set up' says the letters should be written in reverse (in a down clue, letters go up).
'aged'+'ob'='agedob'
'agedob' in reverse letter order is 'BODEGA'.
(Other definitions for bodega that I've seen before include "Small Spanish grocery and wine store" , "Spanish grocery and wine shop" , "Small Hispanic wine-shop" , "Liquor store" , "Shop or cellar in Spain for selling wine" .)