Just had a chat with Support who kindly sorted this out for me;
Currently, the page called Test, placed in the Not Linked section is set as the homepage. In this case, you may want to set the page called Home (in the Main Navigation) as the homepage. You can do it in the Page Settings. Check out this link for more information on this: https://support.squarespace.com/hc/en-us/articles/205814408-Setting-a-homepage