Webley and Scott 400. Screw grip, disc set strikers, no dolls head to get in the way, no integrated striker/tumblers, excellent prewar quality. Intercepting sears are iffy in boxlocks, most have been removed by now.
One of the Rossen patent boxlocks, the self opening one, is really nice, but, there dont seem to be a lot of them out there. Alfred Galifant was going to use that design for his own guns, dont know if he actually completed any.
Richard Levi at G. Granger was working on a 28 gauge boxlock when I was there, self opener, ejector, but, it was just an action forging and bits when I last saw it. Wonder what ever became of it?

Best,
Ted