Currently, the overview page doesn't have a padlock icon, as others pages have. The padlock icon is where users can quickly check the page restrictions, and, in order to check the restrictions applied to the overview pages, the users must go to ... > Restrictions. 

It would be great to add the padlock icon on the Overview page as we have in common pages, so the users could identify through the UI if there is any restriction applied to the space home page.

• Overview page: 
  
• Common page:
  

Workaround

Currently, a possible workaround would be a user with the necessary permissions to navigate to Space Settings > Permissions > Restricted pages and check if the 'Home' page is listed there as a restricted page. If so, the same user would check if it is possible to remove all the restrictions applied or add new users with the 'can edit' or 'can view' permission.