When you duplicate a layout, you are making copies of the instances of object types that are present in that layout.
So it is natural that renaming an instance of the object type in the duplicated layout ends up renaming the object type in the original layout since it is a single object type all along.
And referring to the name of instances in the event sheet is all fine and one of the strengths of Construct 2.
When using an event sheet applied to a layout, the events only apply to the instances of that layout.
The interest of duplicating layout is to be able to use a common event sheet.
Generally, you will have a "Common" event sheet containing mechanics that are common to all your layouts.
For example, clicking on a button and possibly having a callBack from there.
Then, specific event sheet for each layout will be created (containing the specific callBack for each layout) and including the common event sheet.
At last r241 is a beta release the link of which can be found at the bottom of any page of the website and in this page.
See this example made in r241.
Thanks for your detailed reply on this I presume the idea is to have one layout (which is what 99Instances2Go was saying) and then change the behaviour of the buttons etc depending on what they do etc.
However being a little old fashioned for this project only I will probably stick with what I am doing.
Thanks for the link to the beta release and the link for the example