Well-organised attendant (7)
I believe the answer is:
orderly
This clue is a double definition.
'well-organised' is the first definition.
(I've seen this in another clue)
'attendant' is the second definition.
(orderly is a kind of attendant)
(Other definitions for orderly that I've seen before include "Systematically, not haphazard" , "Junior Army rank" , "Batman" , "Regular - soldier" , "Well-behaved -- soldier attending to a superior officer" .)