I asked Iron Science whether they are likely to stock rice protein. So far, they have the cheapest pea protein by bulk (£5/kilo when you buy £5) and cheap soy protein, and they say they'll do rice protein too if enough people ask for it.
As they undercut MyProtein.co.uk (who, in turn, undercut them with their price-matcher service), this could start a price war between the two!
So, email them! Hopefully we can get some more competition on the market and a new source of rice protein (as myprotein seem to be out of stock whenever I look).