James,
The problem with it being British, is that there is a crowned view mark, but no corresponding proof mark. Both should be present.
Pictures of more than close-ups would help, although I do see an overall photo.
Lock style looks French to me, but early English and Italian are also in the running.
A good square-on close-up of the full lock would help.
Fluted barrels were often Italian, but not always.
All best,
R.