Using 4.8 I'm trying to add a custom section with a tree, and I have 

I'm not at all certain what the treeHandlerType setting should be.

I have the following code so far, and this is compiled into a DLL called pps.website.Logic.dll and I wonder if the Handler type should be loadEnquiries or Tree.loadEnquiries

using System;
using System.Data;
using System.Data.Entity;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using umbraco.cms.presentation.Trees;
using pps.website.Logic.ObjectModel;
namespace pps.website.Logic.Tree
{
    public class loadEnquiries : BaseTree
    {
        private DbSet<ef5EnquiryData> enqset;
        public loadEnquiries(string application) : base(application)
{
            var context = new PpsContext();
            enqset = context.Enquiries;
        }
        protected override void CreateRootNode(ref XmlTreeNode rootNode)
        {
            rootNode.Icon = FolderIcon;
            rootNode.OpenIcon = FolderIconOpen;
            rootNode.NodeType = TreeAlias;
            rootNode.NodeID = "init";
        }
        public override void Render(ref XmlTree tree)
        {
            foreach (ef5EnquiryData enq in enqset)
            {
                XmlTreeNode xNode = XmlTreeNode.Create(this);
                xNode.NodeID = enq.Id.ToString();
                xNode.Text = string.Format("{0} - {1}", enq.Created, enq.Name);
                xNode.Icon = "enquiry.gif";
                xNode.Action = "javascript:openEnquiry(" + enq.Id.ToString() + ")";
            }
        }
        public override void RenderJS(ref System.Text.StringBuilder Javascript)
        {
            Javascript.Append(
                @"
                    function openEnquiry(id) 
                    {
                        parent.right.document.location.href = 'showEnquiry.aspx?id=' + id;
                    }
                ");
            }
}

No matter what I do the break points set on this are never hit and the tree never loads.

I'm also confused that there are no other rows in these tables. Is there some other way to declare the custom section / tree now?