Gorzag Gitstompa and Nikkit are now available on the Games Workshop Online store for 1 Week Only. I did check and apparently its not quite available yet in the US or Canada. Everywhere else seems ready to go.
I am assuming the US and Canada will get it shortly....
Here is the link assuming it will work later for those of us in the US/CA
Gorzag Gitstompa and Nikkit £21