Fruit, choice, next to one of London's stations (8,4)
I believe the answer is:
victoria plum
'fruit' is the definition.
(I've seen this before)
'choice next to one of london's stations' is the wordplay.
'choice' becomes 'plum' (both can mean excellent).
'next to' says to put letters next to each other.
'one of london's stations' becomes 'Victoria' (Victoria is a London train station).
'plum' put after 'victoria' is 'VICTORIA PLUM'.
(Other definitions for victoria plum that I've seen before include "Red fruit" , "Preserve item" , "Variety of fruit" , "Fruit called after queen" .)