John Bull Salt Shaker

The key to Attebury vs Imperial is that the later issue Imperial shaker is marked with the IG trandmark.  But if it is hard to see the mark, then look at the buttons on his coat.

 

The Real John Bull has Two rows of buttons. (2 buckles, 4 buttons) The Imperial Glass Co John Bull has Three Rows of buttons (2 buckles, 6 buttons)
Difficult to see from the photo,  but for this one, the hair is more detailed Glass is heavier than the original but would be hard to tell without both side by side.

 

 

The Imperial glass Bull has the IG trademark on the base.

 

The later issue IG Carnival John Bull is the same mold as the earlier IG milk glass shaker  

 

 
The mark is easier to see on the carnival shaker