Hi, when i load my game with my new esp all that's left is the door, door marker and north marker in my new cell . When i load the ESP back into the construction set its the same. Is this common and can i fix it?? I have both expansions and numerous mods btw.

Your description is a little vague. But it sounds like you are loading your changed plugin with the same savegame. This is likely to cause problems of disappearing and doubled items due to the Construction Set renumbering reference numbers when you make changes in a cell, sometimes called the localref problem. The solution is to start a new game after you have made any changes to a cell. You can verify if this is the problem by starting a brand new game, using coc to visit your cell and checking to see if everything is ok. If it is when you start a new game, but things are missing or doubled when you use your plugin with a saved game, then I think it's the localref problem.

Wrye Mash is a wonderful thing.

I just keep a clean save that I can load into for testing, easier than Mash or restarting.

Yes thank you, that was the problem!! Sorry for being vague What is this Wrye Mesh you are speaking of O wise one??????

http://wryemusings.com/Wrye%20Mash.html is a very useful tool. It can do many things like manage mods, repair savegames. You an also use the Mod Updating procedure described in that document to update cell references when you change a plugin. But like peachykeen says, it's easier just to start with a clean save.