At least for the double rifles, the boxlocks were made by Samuel B Allport or Richard Ellis among others.
I have one of each. The SBA one is nicer.
The Purdey records (dimension books) will say which, if you get a picture and know how to read it. Look at the "stocker" .
SBA is Allport and RE is Ellis.
Richard Ellis was amalgamated with Webley and WC Scott in the late 1890s.
SBA was a top quality maker.
Best regards,
WC-