I hadn't seen this anywhere else on the site, so thought I'd let people know. The new 12" MacBook is now available in the Refurbished section of the UK Apple Store site. This is the first week it has been available since it was launched in the UK. Up to £200 pounds of the retail price.
They've actually been on there for nearly three weeks! But, yes, it's a pretty good deal - good enough that I bought one, anyway ETA: I see they now have a "MacBook" section - previously they were quite hidden.
Before I bought mine, I tried to look for the refurbished one here in the US. They had none. I went to look on the site, they have some! However, my savings is only about 115.00 including tax. Not sure if it's even worth it to get a refurb.