Soldier sitting on own special low wall (7)
I believe the answer is:
parapet
'low wall' is the definition.
(I've seen this before)
'soldier sitting on own special' is the wordplay.
'soldier' becomes 'para' (para is a kind of soldier).
'sitting on own special' becomes 'pet' (I can't explain this - if you can you should believe this answer much more).
'para'+'pet'='PARAPET'
Can you help me to learn more?
(Other definitions for parapet that I've seen before include "Wall, a low sort" , "protection from fire" , "Defensive line" , "Wall's top" , "form of protection" .)