Awkward, this being left in Calais (6)
I believe the answer is:
gauche
I believe this is a double definition.
'awkward' is the first definition.
(I've seen this before)
'being left in calais' is the second definition.
('left' in French eg in Calais)
'this' acts as a link.
(Other definitions for gauche that I've seen before include "Clumsy, socially awkward (6)" , "Clumsily tactless" , "Socially awkward or tactless" , "Unsophisticated and socially awkward" , "Like maladroit people" .)