public string Create(long accountNumber, OrderLine orderLine, string encryptionKey)
        {
            var stringToHash = string.Concat(accountNumber, orderLine.OrderRef, orderLine.ItemNumber, orderLine.Description, orderLine.Description2, orderLine.Description3,
                orderLine.Description4, orderLine.Description5, orderLine.Quantity, orderLine.Amount, orderLine.VatAmount, orderLine.VatPercentage, encryptionKey);

            return CreateHash(stringToHash);
        }
 public string AddOrderLine(long accountNumber, OrderLine orderLine, string hash)
 {
     return Client.AddSingleOrderLine2(accountNumber, orderLine.OrderRef, orderLine.ItemNumber, orderLine.Description, orderLine.Description2, orderLine.Description3, 
         orderLine.Description4, orderLine.Description5, orderLine.Quantity, orderLine.Amount, orderLine.VatAmount, orderLine.VatPercentage, hash);
 }