So I have to ask, how does one work out a rough age of a Bengall? I've noticed there are some that have the word 'Bengall' beside a floral type logo, and then there are others that just have the plain word with no other image, other than the makers name on the other side.

I've read here about the post 1891 identification, due to inclusion of the word 'England' - but that seems to be all I can find. How do we figure out a rough age?