I am trying to call into my controller method passing 2 parameters but the controller action is never hit and a 404 error is returned.

having looked at other similar questions I have tried reformatting the actionlink and also tried using @html.action, made sure that it is a HttpGet rather then a HttpPost and obviously made the action method is actually there in the controller.

Action result:

     @Html.ActionLink(
                   linkText: item.FileName,
                   actionName: "GetStatement",
                   controllerName: "Statements",
                   routeValues: new { id = item.Id, entityCode = 
    item.EntityCode },
                   htmlAttributes: null)

Controller method

public class StatementsController : Controller
    {
        [HttpGet]
        public ActionResult GetStatement(int id, int entityCode)
        {
           //go to repository and get statement
        }
    }

I am also not sure that the corresponding URL is formatted correctly: Statments/GetStatement/1234?entityCode=111

Please check this one you need to change some small pieces of code.

In cshtml page

 @Html.ActionLink(
                   linkText: item.FileName,
                   actionName: "GetStatement",
                   controllerName: "Statements",
                   routeValues: new { itemid = item.Id, entityCode = 
    item.EntityCode },
                   htmlAttributes: null)

Controller code

public class StatementsController : Controller
    {
        [HttpGet]
        public ActionResult GetStatement(int itemid, int entityCode)
        {
           //go to repository and get statement
        }
    }

Note: when you pass "Id" in controller action then automatically route convert in below example

public ActionResult HandleException(int id)
        {
            // id mentioned in **RouteConfig** file that's way URL automatic mapped
        }

See the RouteConfig file

public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {                
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
            );
        }            
    }