No Trace of Tracy..what was the point?
The gypsies plan was the guy needed to be in that room and conscious at 4pm when the girl got off the bus and into the house. But why does that matter at all? Whether he tells the police he was unconscious or conscious at that time, what does it matter? He was being made to look like he was being robbed (who opened the safe anyway??), after knocking him out just leave him there or put him back after they kidnap the girl...job done and no need to spend countless months building an exact replica. They had witnesses who saw the girl enter which was basically the only thing that mattered.
The only reason for the new room would have been for the sake of the plot surely, otherwise this wouldn't have been a Jonathan Creek episode.