Cocktail of wine duly hard to handle (8)
I believe the answer is:
unwieldy
'hard to handle' is the definition.
(something unwieldy is hard to handle or control)
'cocktail of wine duly' is the wordplay.
'cocktail of' indicates anagramming the letters (a mixture of the letters).
'wine'+'duly'='wineduly'
'wineduly' anagrammed gives 'UNWIELDY'.
(Other definitions for unwieldy that I've seen before include "Cumbersome" , "Difficult to handle" , "Large and awkward to carry or manage" , "Ponderous" , "Awkward to move because of shape and weight" .)