Hey Danny,
James here, I was helping someone out with this when I found your question and thought I would help out, as we got it working.
If you have it setup like this it should work.
Also, your form needs to have a first name and last name field added to it, if you use those fields in Genesis.
If you’re still having issues, just pop me an email, I work at Mad Mimi and would be happy to get that setup for you.