It appears that the issue was that the email was already in the database, I suppose this must be the case for most people testing a site, however I didn't know that until I turned on the maximum error reporting and debug and changed the template.

The change of your template is what did it. It's missing the Joomla message include. This means you can't see any message queues. So errors, notices, success messages, etc.. are all hidden from you and your users. CB is designed to use the queue during redirects, etc.. so without the message include you're going to be "in the dark" regarding a lot of things. I recommend contacting your template developer and seeing if they will add the message include in. It is as follows.

<jdoc:include type="message" />