I see nothing wrong about the serial number; the "W" is blurred from the polishing, but it is there and the number is in the British range.*

As I said, it has been heavily polished and hot tank blued, seriously reducing the value. Unlike some WWII era .45 pistols sent to Englandicon, those .455's were issued and used. One in excellent condition is pretty rare. (Mine has a decent finish, but someone scratched his initials in the slide; it is going to stay just that way, if he was an RAF flyer, I owe him at least that.)

*Those pistols were numbered in the regular government model series; only the "W" marked them as .455 caliber with a different frame.

Jim