[E2013] [TA] [C#] [Windows]: Error installing transport agent on Exchange 2013

Hi,

Pretty new to Exchange Development and I'm trying to install the transport agent from this blog: https://blogs.technet.microsoft.com/appssrv/2009/08/26/how-to-control-routing-from-your-own-routing-agent/ but not having any luck.

The error I get is:

The TransportAgentFactory type "RoutingAgentOverride.SampleRoutingAgentFactory" doesn't exist. The
TransportAgentFactory type must be the Microsoft .NET class type of the transport agent factory.
Parameter name: TransportAgentFactory
    + CategoryInfo          : InvalidArgument: (:) [Install-TransportAgent], ArgumentException
    + FullyQualifiedErrorId : [Server=QA-EXCH13-01,RequestId=86424b9f-edc1-4b6b-8450-a497b08c899c,TimeStamp=13/11/2016
    11:22:47] [FailureCategory=Cmdlet-ArgumentException] 2C8C2427,Microsoft.Exchange.Management.AgentTasks.InstallTra
  nsportAgent

The command I'm using is:

Install-TransportAgent -Name "RoutingAgent" -AssemblyPath "C:\RoutingAgentOverride.dll" -TransportAgentFactory "RoutingAgentOverride.SampleRoutingAgentFactory"

The top part of the code as per the blog:

namespace RoutingAgentOverride
{
    public class SampleRoutingAgentFactory : RoutingAgentFactory
        {
            public override RoutingAgent CreateAgent(SmtpServer server)
            {
                RoutingAgent myAgent = new ownRoutingAgent();
                return myAgent;
            }
        }

So I think I've got the command right and testing out the installation on a Exchange 2016 server it sucessfully installed, however on my Exchange 2013 CU14 server it does not.  I am using the same versions of the Microsoft.Exchange.Data.Transport.dll and Microsoft.Exchange.Data.Common.dll that come with Exchange 2013 CU14

I tried the fixit script in https://support.microsoft.com/en-us/kb/2938053 but that made no difference.

Is anybody able to suggest anything that I can do to get the transport agent installed on my Exchange 2013 box?