Swimmer wants British wine, not European (8)
I believe the answer is:
brisling
'swimmer' is the definition.
(brisling is a kind of fish)
'wants british wine not european' is the wordplay.
'wants british' becomes 'b' (I can't justify this - if you can you should give a lot more credence to this answer).
'wine' becomes 'riesling' (Riesling is an example).
'not' indicates named letters should be taken away.
'european' becomes 'E' (abbreviation e.g. EU).
'riesling' with 'e' taken away is 'risling'.
'b'+'risling'='BRISLING'
Can you help me to learn more?
(Other definitions for brisling that I've seen before include "Swimmer" , "Small fish of the herring family" , "Norwegian fish" , "Sprat sold in a can" .)