Miller, you're right about that mark being a Birmingham date code, starting in 1921. It was dropped in 1941, then reintroduced in 1950. If you can read the letter, which can be difficult sometimes, it's a good way to date a Brit gun. However, the London Proof House didn't use the mark or any other date code until 1972. After that, their code is pretty simple: LP with the last two digits of the year underneath.
Terry, do you see anything on the water table of the 2nd gun to indicate it's British? I can't see all the marks clearly, but the perron and the PV--which I can see clearly--are certainly Belgian.
