Thanks Edwin.
The two custom fields I am trying to upload are called Object and Tags and for some reason neither of them are uploading.
Could it be because of their Attribute Type?
Object is a Drop Down List (Multi Value)
Tags is a Drop Down List
Also, I noticed something in the help area about Test Folder not being able to be imported when linking with a test case. Does this mean Test Folder cannot be uploaded at all?
Thank you for the continued support!