WFC Restful Service Method Not Allowed "POST" ISS Configuration

successful ISS configuration for "GET" Method but not for "POST" Method. (method not found error)

A wfc rest service but i get method not found error.  I also have som "GET" methods that work fine..

Interface:

[ServiceContract]
   public interface INavigatorWebService
   {
      [OperationContract]
      ApiReturn GetApiAlive(string apikey);
      [OperationContract]
      BookingData PostBookingData(BookingFields incomingFields);
   }

[DataContract]
   public class BookingFields
   {
      [DataMember(Name = "registrationNumber", EmitDefaultValue = false)]
      public string registrationNumber { get; set; }
      [DataMember(Name = "vehicleMake", EmitDefaultValue = false)]
      public string vehicleMake { get; set; }
      [DataMember(Name = "vehicleModel", EmitDefaultValue = false)]
      public string vehicleModel { get; set; }
   }

Service:

[WebInvoke(Method = "POST",
           BodyStyle = WebMessageBodyStyle.WrappedRequest,
           RequestFormat = WebMessageFormat.Json,
           ResponseFormat = WebMessageFormat.Json,
           UriTemplate = "PostBookingData")]
      public BookingData PostBookingData(BookingFields incomingFields) { // }

Web Config:

<?xml version="1.0"?><configuration><system.serviceModel><services><service name="DmsNavigator.NavigatorWebService" behaviorConfiguration="DmsNavigatorServiceBehaviour"><host><baseAddresses><add baseAddress="http://webservice.dmservices.co.uk" /></baseAddresses></host><endpoint name="epcfg"  address="http://webservice.dmservices.co.uk/DmsNavigator.NavigatorWebService.svc"
                      behaviorConfiguration="DmsNavigatorServiceEndPointBehaviour"
                    binding="webHttpBinding"
                    contract="DmsNavigator.INavigatorWebService"/></service></services><behaviors><serviceBehaviors><behavior name="DmsNavigatorServiceBehaviour"><serviceMetadata httpGetEnabled="true"/></behavior></serviceBehaviors><endpointBehaviors><behavior name="DmsNavigatorServiceEndPointBehaviour"><webHttp /></behavior></endpointBehaviors></behaviors></system.serviceModel></configuration>

thanks in advance