Extending K13 Page Listing Module to include DocumentCreatedWhen

Hi,

I've created a custom module to extend the Listing view to include the DocumentCreatedWhen column like so:

using CMS;
using CMS.Base.Web.UI;
using CMS.DocumentEngine;
using CMS.UIControls;

// Register the extender for the Content Listing page
[assembly: RegisterCustomClass("ContentPageListingExtender", typeof(ContentPageListingExtender))]

public class ContentPageListingExtender : ControlExtender<UniGrid>
{
    public override void OnInit()
    {
        Control.AddColumn("Date Created", nameof(TreeNode.DocumentCreatedWhen));
    }


}

However, when I go to register the extender, I cannot find the listing section of the content/pages module:

Am I going about this the wrong way? I also tried adding it to CMSModules_Content_Controls_DocumentList as a fallback method (though would prefer to use an extender) and rebuilt the solution but that also didn't work.

Any hints at all would be great!

Thanks,

Rory