Sorry mate I was supposed to get back to you on that and I didn't (did I?).
As Splodge says you can see it if you look from the front left of the engine back behind the exhaust manifold. It's on the front top left hand side of the block, raised up and unpainted. You can read it if you use a torch at the right angle so it casts a shadow. Its two or three letters and four numbers e.g. AB1234.