There was a heavy trade of Belgian parts to England. These included barrels, actions, etc. This is documented at least during the very early 1900's, though the trade had been on going for decades.

So many assume that if a set of barrels was produced in Liege, it had to be proofed there before being shipped to England. More and more, I am of the opinion that they were most likely shipped unproofed and then proofed in England. Making their origin almost impossible to trace. How many times have you seen a set of Krupp barrels on a gun? How often did those barrels have German proof marks?

Pete