Top horizontal menu - Configuration Issues

[MK Automotive]

I'm trying to add more top level categories to my top horizontal menu from withing the admin console, however the list of categories is blank.

 

See Here : http://www.awesomescreenshot.com/image/1989009/56062845f6556044913043cb179fd186

 

There are several categories at the bottom of my page : 

 

See Here : http://www.awesomescreenshot.com/image/1989023/7a8e646529a671e9665914f5485f9894

 

 

Anyone have any idea why this has happened ?  I have already removed and re-added the "top horizontal menu" module (twice).

 

 

I know my way around the database, so I can work out why this is happening if someone can tell me where the "top horizontal menu" stores it's configuration.

 

Thanks