All the best Argentine red, then English port (7)
I believe the answer is:
cheerio
'all the best argentine' is the definition.
I can't tell whether this defines the answer.
'red then english port' is the wordplay.
'red' becomes 'Che' (as in Che Guevara, a communist or 'red').
'then' is a charade indicator (letters next to each other).
'english' becomes 'E' (abbreviation).
'port' becomes 'rio' (Rio de Janeiro is a port).
'che'+'e'+'rio'='CHEERIO'
Can you help me to learn more?
(Other definitions for cheerio that I've seen before include "for so long!" , "good health" , "A final word" , "Informal farewell" , "An informal hearty goodbye" .)