Where can I find black cocoa powder (a.k.a. black onyx cocoa powder) in the UK?
I have prevosly purchaced this via a uk retailer on Amazon 

  

But currently out of stock.

I am aware that these guys 

http://www.savoryspiceshop.com/spices/cocoa-black-onyx.html

Sell internationally, but you have to phone to order, not place the sale online.  I guess so they can get the shipping right.  But to stress I've never used them