Writer knocking back very fine Scottish port (7)
I believe the answer is:
nabokov
'writer' is the definition.
(I've seen this before)
'knocking back very fine scottish port' is the wordplay.
'knocking back' shows that the letters should be reversed in order.
'very' becomes 'v' (abbreviation).
'fine' becomes 'ok' (synonyms).
'scottish port' becomes 'oban' (I've seen this before).
'v'+'ok'+'oban'='vokoban'
'vokoban' backwards is 'NABOKOV'.
(Other definitions for nabokov that I've seen before include "'Russian-American author, famously of Lolita (7)'" , "Russian-American novelist" , "Lolita writer" , "Wrote Lolita and Pale Fire" , "Russian author" .)