As champagne no longer being kept perhaps in the workplace (6)
I believe the answer is:
office
'the workplace' is the definition.
(I've seen this in another clue)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for office that I've seen before include "Post - place of work" , "Where many of us work" , "Where a white-collar worker works" , "employment > service" , "base?" .)