Lots of folks were involved with that one!
Here's an old thread regarding the importer Henry Richards
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=265056Your gun is Belgian, made prior to 1893 but after 1877 (the single inspector's mark appears to be spangled rather than crowned)
Francotte likely supplied the barrels and possibly the action
'JD' was probably the barrel maker
?'LRH' the 2 iron crolle tube maker
Interesting crowned MGB? + another letter on the action flats. I tried to find that but couldn't. One would think
Manufacture something?
https://www.hlebooks.com/daubres/li04.htmMaybe you could chalk the mark and bring out the last letter? That may have been whoever finished the gun.