Very large figure departs for port (6)
I believe the answer is:
ostend
'port' is the definition.
(I've seen this before)
'very large figure departs' is the wordplay.
'very large' becomes 'os' (abbreviation for oversize).
'figure' becomes 'ten' (I've seen this in other clues).
'departs' becomes 'd' (common abbreviation e.g. train timetables).
'os'+'ten'+'d'='OSTEND'
'for' is the link.
(Other definitions for ostend that I've seen before include "Channel port" , "Belgian port and resort" , "Port -- stoned (anag)" , "cross-channel port" , "Port - doesn't (anag)" .)