I have inherited my great grandmother's ring and would like to know how old it is?

by claire lloyd

I've beeen told my ring is 18 ct white gold and there are three diamonds; a large one in the middle and smaller diamonds on either side of the large central diamond. But the only hallmarks are: MBCo/6072 and the last numbers, i think they are 1803.
I would really like to know the age of my ring. There are no other hallmarks and i have been told this is because its an antique, thanks claire lloyd