Manufacturing establishment hard to find in Notts town (8)
I believe the answer is:
workshop
'manufacturing establishment' is the definition.
'hard to find in notts town' is the wordplay.
'hard' becomes 'h'.
'to find in' indicates putting letters inside.
'notts town' becomes 'worksop' (town in Nottinghamshire).
'h' going into 'worksop' is 'WORKSHOP'.
(Other definitions for workshop that I've seen before include "Place where things are made" , "Seminar" , "Place of manufacture" , "Room where goods are manufactured or repaired" , "Room or building in which work or manufacture is carried on" .)