It's what was known as the time as a 2nd quality rifle. "Best" quality was usually reserved for sidelocks; a 2nd quality was typically made to the same standard, but on a less expensive box-lock action. The action is a Webley with a screw-grip top extension (dolls head). This was considered one of the best actions available. You will notice a tiny screw just at the rear of the fences; this is for the intercepting sear or safety. Unusual to see that on a box lock, and again, it indicates a top quality weapon.
Webley may have provided the barreled action to Lang's, or they may have made the complete rifle. Either was common practice and virtually all British gunmakers bought in actions, barreled actions or complete rifles with their name engraved them.
The recoil pad looks to be a replacement, and the scope mounts were added at some later date. Your rifle looks like it has ejectors. Very good calibre but sourcing modern brass is an issue. Woodleigh makes bullets of the proper diameter and weight.
I would love to take that rifle moose hunting.