A grand finale associated with ace programme (6)
I believe the answer is:
'programme' is the definition.
(I know that agenda is a type of programme)
'a grand finale associated with ace' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'finale' becomes 'end' (I've seen this before).
'associated with' says to put letters next to each other.
'ace' becomes 'a'.
(Other definitions for agenda that I've seen before include "Timetable" , "Items for discussion at committee meeting" , "Plan for meeting" , "List of items for discussion by committee" , "To-do list" .)