Interesting thoughts about the tubes fitted by Webley & Scott. Of course that would have required reproof. And unless there was yet another reproof after that (I was unable to tell from the proofmarks I could read on the flats), the reproof for those fitted barrels took place no earlier than 1925. (Chamber length wasn't marked prior to that, other than for guns with exceptionally long chambers.) So the suggestion that the barrels are old stock makes a lot of sense. Not a lot of new Damascus barrels being made after 1925.