Let bloke from Bow attach architectural feature (10)
I believe the answer is:
impediment
'let bloke from bow' is the definition.
'impediment' can be an answer for 'let' (I've seen this before). I'm not sure about the 'bloke from bow' bit.
'attach architectural feature' is the wordplay.
'attach' becomes 'im' (I can't explain this - if you can you should believe this answer much more).
'architectural feature' becomes 'pediment' (I've seen this before).
'im'+'pediment'='IMPEDIMENT'
Can you help me to learn more?
(Other definitions for impediment that I've seen before include "opposition" , "Let" , "Obstacle" , "Hindrance, obstruction" .)