Apologies.

 For the last week, I have been having technical problems with my blog. For some reason, it was having a problem with the guest blog byDavid Siwik (below). Initially, it wouldn't load up the pictures, and then only some of them, and then it missed out the first line that introduced the author. I've got it fixed now, to what it should have been originally, so hopefully it won't go weird on me again.