Thanks, this was really helpful and worked perfectly however it turns out I need a bit more help... I hope this is ok.
My website is www.workio.co - at the bottom of the page is a widget are with 4 footer navigation sections. Above them on most, but not all of the pages, is a section that says "Interested in the Cutting Edge" currently this is added on each page as a content block via cornerstone which makes updating very tedious. What I would love to do is include the code for this content block in the footer section such that it appears on every page and I only have to edit it once. This is why I was asking to add to the footer, but the code you gave me goes in right at the very bottom - sorry for this.
I think what I need to do is add the code just before the footer widget area but after the main body of the content which is controlled in cornerstone.
Does this make sense? Any tips very much appreciated.