This is a copy of a PM which I've just sent to the opening poster. Should it be of any interest to others, please do respond.
I bought my gun at auction, and as I collect Single Triggers, it's why I bought it - - it's too nice to scrap, just for the trigger system!! .

I've just found your post on the Double Gun Shop- from YEARS ago!! I also have a B/L gun by Maleham, and as yours - the same bolstered action body and the same ejector system - the same forend release - but mine has a Boss Single Trigger - and it works well!

My gun is No:1803. The forend flat states Patent 9677.88 150 - I've tried to research this but it only shows something related to medals!
1803 has exceptionally good barrels with the rib reading Arthur Turner (Late Maleham & Co.) 5 West Bar Sheffield.

The ejectors on my gun are very weak - they resemble Boss ejectors, in that they're under pressure from coiled springs, and as Boss, it could be loosely claimed that they assist with opening.

Should you receive this and should you decide to reply, perhaps the best route is via e/mail - - alecswan1@gmail.com

Alec Swan