I have a long knife (pictured with penny for size contrast) labelled Atkinson Bros Sheffield, with clear but unknown markings where the blade meets the handle. Frankly, I am not even sure this is silverplate - I always thought it was some kind of stainless steel, yet there are clear hallmarks (pictured). I also believe the handle is ivorine? Any help would be appreciated. Retrieved from my late grandparents' cutlery drawer.
The hallmarks (pictured) are G.B followed by a crown followed by a lion followed by what appears to be a "D" but may also be a "DJ"?