new and old

I have an existing site using your plugin (which is awesome by the way) using opencart 1.5x
I am building a new system using Opencart V2.
Installed the newer version of your plugin
Exported categories from the new
Exported the old (it has them all in tabs)
Looking only at categories, I compared the header of each column in the spreadsheet, and other than having to delete Language IDs column from the old, and note that (en-gb) is now in many of the meta headings, it all looked simple enough
I copied the contents of my old spreadsheet and pasted it into the new spreadsheet.
Everything appears to marry up without any issue
When I then try to import I get this error

Uploaded spreadsheet file has validation errors!
See also 'System > Tools > Error Logs' for more details.
No server data has been changed.

Looking at the error log I see this message

2016-07-02 5:18:36 - Export/Import: Invalid header in the Categories worksheet

Now, I have checked and double checked, and the headings on the spreadsheet are 100% perfect. This means it must be an issue with the content but I cant seem to see any reason why?
The errors are pretty much pointless (very Microsoftish)

I have an existing site using your plugin

Good for you, but since noone knows, what plugin your'e writing about, noone would be able,
to find out anything...

Therefore, your infos are pretty much pointless (very Microsoftish)
Ernie