Thanks AngryTechnician - that sorted it. Jeez - I wish MS would remember there are other countries in the world and/or make the installer return a useful error message. I know RSAT is very anal about the version of Windows you use so I jumped to the wrong conclusion based on the vague error.
Hi Trapper,
That's interesting - how did you get this to work? When I try and run the preview RSAT "Windows8-RT-KB2693643-x64" on the Technet 8.1 Pro RTM I get an error "The update is not applicable to your computer".
Cheers,
Tim