Antique Victorian monogram 18 carat gold signet ring

Era: Victorian 1837-1901
Materials: 18ct Gold, partial hallmark 
Size: UK O, USA 7.25, EU 55.5
Weight: 10.3 grams
Size: Top panel 12.5x10mm
 
This is a fine, antique 18 carat yellow gold signet ring with an oval top panel and beautiful shaped floral repousse shoulders. It is a substantial ring with a generous use of gold, weighing 10.3 grams. It feels incredible to wear!
 
There is a partial hallmark, crown, makers mark J.N, anchor for birmingham. It has been tested as 18ct Gold with a high 22-24 carat plating to give it the rich buttery yellow tone. I would say it is fairly early Victorian in age C.1840-50.
 
The shoulders taper from 7mm to a 3mm wide band at the reverse, with a solid top panel that is engraved with gothic script initials either C.S or G.S in my opinion, but it is whatever you see it as that matters! There is some wax residue to the top and letters from where it was used originally to seal letters.
 
I suspect from inspecting the shank, it has been previously sized, which may be when some of the hallmark was lost.