Where those in service eat dog's dinner (4)
I believe the answer is:
mess
'dog's dinner' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for mess that I've seen before include "Untidy muddle" , "Meal" , "dish" , "Confused situation" , "Where sailors eat" .)