What info are you looking for? I just Googled "Firth Cutlery Sheffield England" and a page of stuff popped up!
If its value? about 20-$100.00 bucks. Is what i've sold sets like that depending on condition.
I will clean them up and put a new edge on the carver.
There are lots of sets like those here in the US and most people don't have the big roast, Ham, turkey dinners, but maybe a couple of times a year anymore.
There is some interest $$ in the sets in excellent condition but most have been used since the 50s 60's & 70's.