What timber merchants offer for revised trading terms (3,4)
I believe the answer is:
new deal
'revised trading terms' is the definition.
I don't understand the remainder of the clue.
(Other definitions for new deal that I've seen before include "Political recovery plan" , "President Franklin D Roosevelt's economic policy from 1933" , "In time it might be OK for building" , "cure for depression?" , "US Government policy" .)