Representative body starts to deal with something left behind (8)
I believe the answer is:
'representative body' is the definition.
(group of delegates)
'deal with something left behind' is the wordplay.
'deal with' becomes 'de' (I can't justify this - if you can you should believe this answer much more).
'something left behind' becomes 'legacy' (something left in someone's will).
'starts to' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
(Other definitions for delegacy that I've seen before include "Eg a Clyde (anag) - giving authority to others - university department" , "Committee" .)