The Photos being posted are of a Lancaster Sidelock Ejector 450 / 400 3 1/4",
Serial No 13141. It is a "Wrist Breaker" action.
Proofed 60gn Cordite, 400gn Bullet.

Address on barrel 99 Mount St, Berkeley Sqaure, London
26” / 66cm Barrels

Lever locked fore end with Full engraving
Full Length File Cut Rib
1 Standing & 1 Folding leaf sights, Ramp Mounted Bead Foresight
14 1/2” / 37cm, Old English Red Rubber Recoil Pad

The gun was not cased when I got it so I cased it and then my mate
in the US took a liking to it and wanted it so badly I relented.

He took the rifle to Africa in 2004 and shot a Lion, Buffalo and
Elephant in 3 Hours.

Enjoy.

500 Nitro