Thanks for following up. I can't post a capx until I get a little more rep but for now, let me try and explain a little better. When duplicating the entire layout 1, the layout 1 tilemap ( and only tilemap at this stage) exists on layout2. I want to simply delete/remove the tilemap from the layout without affecting layout1. When I delete the timemap object from layout 2 however, it completely deletes it from the object list breaking layout1.
I tried building layout2 from scratch but I cannot get the game resolution to look identical to layout1 for reasons unknown to me. This forced me to try and create the second layout using the 'Duplicate' tool.