When you buy GreenBlog.co.uk you also get GreenBlog.uk as part of the sale.
I've been involved in the UK domain aftermarket since 2008, I'm also a member of Nominet and a Nominet domain registrar. When buying from me, you're guaranteed a quick same day domain transfer once payment has been received. If you see the .co.uk and .uk versions of the same domain listed for sale, both domains will be included in the sale if either domain is bought. As an example, buy hovercraft.co.uk and you'll also get hovercraft.uk as part of the sale.