Managing to reach top of a wall (6)
I believe the answer is:
coping
This might be a double definition.
'managing' is the first definition.
('cope' can be a synonym of 'manage')
'top of a wall' is the second definition.
'coping' can be an answer for 'top' (I have seen 'top of wall' mean 'coping' so perhaps 'top' could also mean 'coping'). I'm not sure about the 'of a wall' bit.
'to reach' is the link.
Can you help me to learn more?
(Other definitions for coping that I've seen before include "Managing, getting by" , "Contending successfully" , "wall feature" , "Managing - top course of a wall" , "Doing well" .)