As it was my job to prepare the zine file and send it to the printers, I have been emailing back and fourth with Adam, part of CBF printers. After receiving the initial quote I wanted to make sure I was making a document which was compatible, and in their preferred format. After my second attempt still wasn't quite right, I rang Adam and he explained to me on the phone exactly what he needed and was incredibly helpful.
Below is our email conversation.
After these messages I rang him as it was much easier to communciate via phonecall, Adam had to explain to me how to format my document as it still wasn't quite right, but I got it in the end.