The box shown here is for the Dinky Toys #503 Foden (1st cab) Flat Truck with Tailboard model.
It is an early type 'Supertoys' style, 'blue wrap', lid & base type box, with the orange label with B&W model illustration.
It is for the early #503 versions of the model in a wide variety of finishes.
If your model is the 2nd cab version, please see our other listings under this model number and also in the Dinky #900-999 section.