Answer to Question 2:

Dear Marion 

With regard to your query the regulations do not state that you no longer have to put up no smoking signage.  Therefore best practice would be that you continue to display the signage.  As a warehouse/production area is usually potentially high risk from a fire point of view, I would use whatever means possible to reduce the risk, and as stated above would advise leaving up the signs.  

In a warehouse setting the area around the goods entrances would probably be where employees may tend to smoke, so this would be the area I would really concentrate on.