So I figured out that this object (there's 21 of them actually all following the same naming convention) can be selected and moved around using the edit multiple entities simultaneously option in Menyoo and using Manual Placement to move it. Not perfect but it works to an extent.
@chonkie Not how I wanted to but it's good enough.
I did discover that the game ignores the folder if there's a problem with content.xml. Just yesterday discovered I had omitted part of the path pointing to one of the meta files and once I corrected it the game loaded the car pack just fine.
If it's a '.cs' file ('LAZERHelper.cs' for example) you just drop it into the 'scripts' folder & it should work automatically if it's set up correctly.
You can open & edit a '.cs' file with a text editor (like Notepad or Notepad++). Worth having a look inside them & making sure the name is correct for the plane you are using it with. If not, change all references to the other plane to the name of the one you are using it with
Point me to the download/s you're talking about & I'll download it/them & have a proper look