This solved my problem!
However, it has led into another problem. I can boot into the windows installer thorough The EFI file however, I can't install windows into the desired partition.
In the guide under the heading Install Windows UEFI as dual boot, step 3 states to format the partition for windows as Mac OS Extended. However, when I do this and format the partition to Mac OS Extended (Journaled), and I go into the windows installer by booting through the EFI file, and I select the desired partition, the option to format is greyed out and a notice is provided stating "Windows cannot be installed to this hard disk space. The partition is of an unrecognised type.". It doesn't seem to be able to format the HFS partition.
I also tried changing the file system to Ms-Dos and exFat but when I format the drive in the windows installer I says "Windows cannot be installed int this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GPT disks.". This makes sense obviously but how do I get around the windows not recognising the Mac OS Extended format and not being able to format it?
Has anyone else had this problem?