ViewCellRenderer reusablecell is ALWAYS null - why?

I dont' get why it's always null.. presumably there's a flyweight impl piggy backing off iOS's tableview renderer here, or this parameter wouldn't exist - but it's always null and as such my cell always get's recreated.. I don't get what's wrong..

here's the codez:

    using System;
    using Xamarin.Forms;
    using TwinEvents.Core.Media.View;
    using TwinEvents.Ios.Media;
    using Xamarin.Forms.Platform.iOS;
    using UIKit;
    using CoreGraphics;
    using System.Threading.Tasks;
    using TwinEvents.Core.Media.Model;
    using SDWebImage;
    using Foundation;

    [assembly: ExportRenderer (typeof(MediaCell), typeof(MediaCellRenderer))]
    namespace TwinEvents.Ios.Media
    {
        internal class NativeMediaCell : UITableViewCell
        {

            UIImageView _imageView;
            UIImageView _thumbnailImageView;

            UILabel _label;
            UILabel _nameLabel;

            public NativeMediaCell (NSString cellId) : base (UITableViewCellStyle.Default, cellId)
            {
                _imageView = new UIImageView (new CGRect (0, 0, 320, 260));
                _thumbnailImageView = new UIImageView (new CGRect (5, 245, 40, 40));
                _label = new UILabel (new CGRect (50, 245, 320, 20));
                _nameLabel = new UILabel (new CGRect (0, 270, 320, 40));
                _label.TextColor = UIColor.White;
                _nameLabel.TextColor = UIColor.White;
                ContentView.AddSubview (_imageView);
                ContentView.AddSubview (_thumbnailImageView);
                ContentView.AddSubview (_nameLabel);
                ContentView.AddSubview (_label);
                ContentView.BackgroundColor = UIColor.Black;
            }

            internal void UpdateValues (IMediaItem item)
            {
                if (item.ImagePath == null) {
                    _imageView.Image = UIImage.FromFile ("placeholder.png");
                } else {
                    _imageView.SetImage (
                        url: new NSUrl (item.ImagePath.AbsoluteUri), 
                        placeholder: UIImage.FromBundle ("placeholder.png")
                    );

                }

                if (item.UserThumbnailPath == null) {
                    _thumbnailImageView.Image = UIImage.FromFile ("placeholder.png");
                } else {
                    _thumbnailImageView.SetImage (
                        url: new NSUrl (item.UserThumbnailPath.AbsoluteUri), 
                        placeholder: UIImage.FromBundle ("placeholder.png")
                    );
                }
                _nameLabel.Text = item.Name;
            }

            public override void LayoutSubviews ()
            {
                base.LayoutSubviews ();
                _imageView.Frame = new CGRect (0, 0, Frame.Width, 260);
                _thumbnailImageView.Frame = new CGRect (5, 245, 40, 40);
                _label.Frame = new CGRect (50, 245, Frame.Width - 50, 20);
                _nameLabel.Frame = new CGRect (50, 270, Frame.Width - 50, 40);
            }

        }


        public class MediaCellRenderer : ViewCellRenderer
        {
            public MediaCellRenderer ()
            {
            }


            NSString cellId = new NSString ("Cell");

            public override UITableViewCell GetCell (Cell item, UITableViewCell reusableCell, UITableView tv)
            {
                NativeMediaCell nativeCell = reusableCell as NativeMediaCell; 

                if (nativeCell == null) {
                    nativeCell = new NativeMediaCell (cellId);
                }

                var mediaCell = item as MediaCell;
                nativeCell.UpdateValues (mediaCell.Item);
                return nativeCell;
            }


            //
            //      protected override void OnElementPropertyChanged (object sender, System.ComponentModel.PropertyChangedEventArgs e)
            //      {
            //          base.OnElementPropertyChanged (sender, e);
            //          if (e.PropertyName == "Item") {
            //              UpdateValues (((MediaCell)sender).Item);
            //          }
            //      }
            //

        }
    }