Hey Jog,
The geck just crashing is strange, is there no message at all?
Its crashing on load of the mods, the only message I get is the Windows Error Report option message.
If you just edit that other mod, then work on a copy of it, don't create an additional esp.
Yeah, as much as I hate having to begin again from scratch that's what I have done.
Everything in a mod is identified by numeric FormIds (the minimized column in each table) the two leftmost digits are the number of the mod and are created dynamically when the game loads, thus everything a mod uses needs to be contained in its own ESP, or in an ESM it has as master
You can add stuff from one ESP to another, by loading the one you want to copy to as active file, and just select the other plugin. But you need to copy all stuff required from the other mod in that session. If you want to use an armor from another mod, for example, you can't just equip your own NPCs with that armor, you have to make a copy of the armor and use this one.
Ah, ok I did kinda thing about that but I though I would need the Fallout.esm for it to work, so I can atleast recover the work I have done, cool

Out of the same reason you can't add objects to another ESP (i.e. place your own NPC into that other mod's cell) the other mod doesn't know your ESP, and your ESP doesn't load the other first. The only way to do this is to convert the other mod into an ESM first (using TESsnip or FNVEdit, not just renaming) But when you edit the original mod anyway, you can just as well add your stuff to the ESP.
Now that you say it, that makes sense and as for the conversion to ESM I just would not have though of it, guess I need more experience at this modding stuff
Another way to merge mods is using TESsnip to copy stuff from one to the other, this way you have more control about what's actually integrated to the other mod than you would have using the GECK, but this is only useful when you actually have two mods you want to merge, if you want to start from scratch with your modifications, edit the original ESP directly or convert it into an ESM and load that ESM as master file in addition to FalloutNV.esm.
Yeah I got to start learning to use these things lol
If you just convert the other mod to a master file but don't rename it to .ESM, your finished plugin-modification *would* actually work even with the original version of the other mod, but this is bound to fail as soon as the loading sequence changes (i.e. your ESP is loaded before the other ESP).
This sounds like the way for me to go, Its fairly much what I wanted to be doing but just did not realise it is what I needed to do.
As for vanishing objects, it might be this issue: http://www.gamesas.com/index.php?/topic/1160217-forgetful-geck-npc-placing-issue/page__view__findpost__p__17020323__fromsearch__1
If your mod contains objects of at type that is new in FNV (casinos, casino chips, weapon mods etc.), the GECK has a bug that let's it store random new objects you created (e.g. statics or NPCs) after new cells in the ESP. In consequence, the cells are loaded before those objects, and the next time you load the ESP, new object from your mod vanish from cells they were placed in.
So, If I understand correctly from what you have said and what I read in the linked thread I would have to move [cut/paste] the objects that are going missing
in the object list, kind of like sorting the loadorder except different, using TESsnip, not FNFEdit.
Thanks for the great reply and info (and link!), given me a bit to think about and some think new to do to, (converting esp to esm).